Methods and compositions for improved comfort contact lens

ABSTRACT

In one aspect, the present disclosure relates to a contact lens comprising a disclosed lubricious surface layer. In a further aspect, the lubricious surface layer comprises a polyacrylamide, e.g., a poly(N,N-dimethylacrylamide. In various aspects, the lubricious surface layer is formed at the surface of a contact lens. In a further aspect, the lens can be a hydrogel lens. In a further aspect, the lens can be a silicone hydrogel lens. The present disclosure also pertains to methods of forming the disclosed lubricious surface layers on a surface of a contact lens. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a continuation of U.S. Non-Provisional applicationSer. No. 16/649,555, filed on Mar. 20, 2020, which is a National Stageof International Application No. PCT/US2018/054372, filed Oct. 4, 2018,which claims the benefit of U.S. Provisional Application No. 62/568,008,filed on Oct. 4, 2017, each of which is incorporated herein by referencein its entirety.

BACKGROUND

Almost 17% of new contact lens wearers drop out in the first year ofwear, which is a major concern for the contact lens industry. Discomfortand dryness are the leading causes, accounting for almost 50% of thedrop outs. In spite of the continuous improvements in lens design, alarge proportion of contact lens users experience at least some form ofdryness and discomfort, particularly towards the end of the day. Themechanisms that cause the dryness and discomfort are complex and notcompletely understood. A number of researchers have examined thecorrelation between various lens properties and discomfort and dryness.A recent study showed that excessive lens movement, inferior lensdecentration, poor surface wettability and deposits, inferior cornealstaining, and Asian ethnicity are associated with dryness anddiscomfort. Comfort data for several different lens types showed asignificant correlation with the coefficient of friction. No correlationbetween comfort and oxygen permeability, modulus and water content hasbeen shown. A correlation between comfort and friction coefficientsuggests that the friction coefficient is the key lens propertyassociated with the end of day comfort, irrespective of the techniqueused in the measurement. The correlation of dryness and discomfort tolubricity is related to the rapid motion of the upper eyelid over thecontact lens surface during a blink. It is believed that lubricity andwettability impact dryness and discomfort, and so significant effortshave been made to improve both of these properties.

Efforts to improve wettability have focused on incorporation of highlyhydrophilic monomers, plasma surface treatments and addition of internalwetting agents such as polyvinyl alcohol (PVA) or polyvinyl pyrrolidone(PVP). Extended release of PVA incorporated in Focus DAILIES® (CIBAVision) into the tears improves comfort. Incorporation of PVP in Acuvue®Oasys™ with Hydraclear™ Plus lenses (Johnson and Johnson) increaseswettability, eliminating the need for surface treatment typicallyrequired in silicone hydrogel contact lenses. Contrary to the PVAincorporation, the PVP loaded in lenses remains trapped due to the highmolecular weight but appears to partially diffuse to the surface toincrease the wettability. Hyaluronic acid (HA) has been explored as apotential biocompatible comfort enhancer and lenses loaded with sodiumhyaluronate (Hyaluronate Gel) have been commercialized (Safigel™).

The incorporation of wetting and comfort agents in contact lenses hasnot relieved the experience of discomfort and dryness for many patients.Lens modifications have included designing better formulations ofrewetting drops and lens care solutions to improve the comfort. PVA, PVPand HA have been used in artificial tears and rewetting drops forcontact lenses. Addition of surfactants in rewetting drops and lens caresolutions has been found to be beneficial, most likely due to improvedwettability of the surface due to surfactant adsorption. The adsorbedand absorbed surfactant desorbs with time, possibly leading to thereduced end of day comfort. Preservatives included in the formulationscan absorb into the lenses and then desorb during lens wear, which couldlead to patient discomfort and potential toxicity issues.

Mayhan et al. U.S. Pat. No. 4,589,964 teaches a method to generate asubstrate with peroxy groups thereon and initiate polymerization ofwater soluble monomers from surface generated radicals. Bertrand et al.U.S. Pat. No. 5,274,028 teaches a method to surface graft a hydrophilicpolymer on a semi-solid polymer substrate with hydroperoxide groups onthe surface in the presence of a variable valence metal ion in a reducedstate.

Despite advances in research directed toward improved lubricity andwettability in contact lens, a significant percentage of contact lensusers discontinue use of contact lens due to discomfort and dryness.Moreover, compositions directed to increasing comfort and decreasingdryness are associated with desorption and release of the wetting and/orlubricious agents into the eye. These needs and other needs areaddressed by the present disclosure.

SUMMARY

In accordance with the purpose(s) of the present disclosure, as embodiedand broadly described herein, the present disclosure, in one aspect,relates to a contact lens comprising a disclosed lubricious surfacelayer. In a further aspect, the lubricious surface layer comprises apolyacrylamide, e.g., a poly(N,N-dimethylacrylamide. In various aspects,the lubricious surface layer is formed at the surface of a contact lens.In a further aspect, the lens can be a hydrogel lens. In a furtheraspect, the lens can be a silicone hydrogel lens. The present disclosurealso pertains to methods of forming the disclosed lubricious surfacelayers on a surface of a contact lens.

Disclosed are hydrogel contact lens, comprising a surface layer ofrelatively uniform thickness comprising a non-ionic hydrophilic polymer,wherein the surface layer has a water swelling ratio greater than 200%.

In a further aspect, the present disclosure pertains to methods ofpreparing a surface layer thereon, comprising providing a hydrogelcontact lens body; loading the hydrogel contact lens body from anaqueous solution comprising a tertiary amine to form a tertiary amineloaded silicone hydrogel contact lens body or from an aqueous solutioncomprising a radical initiator to form a radical initiator loadedsilicone hydrogel contact lens body; providing an aqueous solutioncomprising a monomer for a non-ionic hydrophilic polymer for use withthe radical initiator loaded silicone hydrogel contact lens body or theaqueous solution comprising a monomer for a non-ionic hydrophilicpolymer and further comprising a radical initiating oxidizer for usewith the tertiary amine loaded silicone hydrogel contact lens body;contacting the tertiary amine loaded hydrogel contact lens body or theradical initiator loaded hydrogel contact lens body with the aqueoussolution comprising the monomer; polymerizing the monomer at the surfaceand/or in the surface and a surface adjacent portion of the tertiaryamine loaded hydrogel contact lens body or the radical initiator loadedsilicone hydrogel contact lens body to form a non-ionic hydrophilicpolymer film; terminating the radical; and isolating a lubricioushydrogel contact lens.

In various aspects, the present disclosure pertains to a contact lenscomprising a surface layer formed by a disclosed method.

Other systems, methods, features, and advantages of the presentdisclosure will be or become apparent to one with skill in the art uponexamination of the following drawings and detailed description. It isintended that all such additional systems, methods, features, andadvantages be included within this description, be within the scope ofthe present disclosure, and be protected by the accompanying claims. Inaddition, all optional and preferred features and modifications of thedescribed aspects are usable in all aspects of the present disclosuretaught herein. Furthermore, the individual features of the dependentclaims, as well as all optional and preferred features and modificationsof the described aspects are combinable and interchangeable with oneanother.

BRIEF DESCRIPTION OF THE FIGURES

Many aspects of the present disclosure can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the present disclosure. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

FIGS. 1A and 1B show representative data for a disclosed composition.FIG. 1A shows the release of DMA and TEMED from a DMA and TEMED infusedACUVUE® TruEye®lens versus time FIG. 1B shows the release of APS from anAPS infused ACUVUE® TruEye® lens vs time.

FIG. 2 shows representative data for release of APS, DMA and TEMEDversus time from O2 Optix™ lens infused with the component measured(i.e., test lens was infused with APS, DMA, or TEMED to measure therespective release of each).

FIG. 3 shows a representative plot of the water weight versus poly(DMA)film thickness on an ACUVUE® TruEye® lens, according to an aspect of thepresent disclosure by weight.

FIG. 4 shows a representative plot of water content of the contact lensversus polymerization time for an ACUVUE® TruEye® contact lens modifiedto have a poly(DMA) lubricious coating, according to an aspect of thepresent disclosure, made by using 40 wt % DMA, 30 wt % TEMED and 3 wt %APS where the polymerization time was varied.

FIG. 5 shows a representative plot of water and poly(DMA) mass of thecontact lens versus polymerization time for an ACUVUE® TruEye® contactlens modified to have a poly(DMA) lubricious coating, according to anaspect of the present disclosure, made by using 40 wt % DMA, 30 wt %TEMED and 3 wt % APS where the polymerization time was varied.

FIG. 6 shows a representative plot of the dried poly(DMA) layer mass ofthe contact lens versus polymerization time for an ACUVUE® TruEye®contact lens modified to have a poly(DMA) lubricious coating, accordingto an aspect of the present disclosure, made by using 40 wt % DMA, 30 wt% TEMED and 3 wt % APS where the polymerization time was varied.

FIG. 7 shows a representative plot of the release of timolol fromACUVUE® TruEye® contact lens modified to have a poly(DMA) lubriciouscoating, according to an aspect of the present disclosure, using 40 wt %DMA, 30 wt % TEMED, and 3 wt % APS.

FIG. 8 shows representative stacked FTIR spectra for pure poly(DMA) andan untreated ACUVUE® TruEye® contact lens as indicated, and also for aACUVUE® TruEye® contact lens modified using 40 wt % DMA, 30 wt % TEMEDand 3 wt % APS for the indicated reaction times, according to an aspectof the present disclosure. The comparison sample, poly(DMA) was preparedas described herein below in the Examples.

FIG. 9 shows a representative plot of peak area at 1630 cm⁻¹ vs.polymerization time, for ACUVUE® TruEye® contact lenses modified using40 wt % DMA, 30 wt % TEMED and 3 wt % APS.

FIG. 10 shows a representative plot of peak area at 700 cm⁻¹ vs.polymerization time, for ACUVUE® TruEye® contact lenses modified using40 wt % DMA, 30 wt % TEMED and 3 wt % APS.

FIGS. 11A-11D shows representative photographs of the water contactangle of an ACUVUE® TruEye® lens (FIGS. 11A and 11C) and modified with adisclosed lubricious coating (FIGS. 11B and 11D), according to an aspectof the present disclosure where the contact lenses were modified using40 wt % DMA, 30 wt % TEMED and 3 wt % APS with a polymerization time of15 seconds and oxygen exposure to terminate the polymerization.

FIG. 12 shows representative contact angle data for an ACUVUE® TruEye®lens, according to an aspect of the present disclosure, modified using40 wt % DMA, 30 wt % TEMED and 3 wt % APS with oxygen exposure toterminate the polymerization, thereby providing a lubricious layercomprising poly(DMA).

FIG. 13 shows a scheme for a disclosed process of redox initiatedpolymerization which can provide a thin lubricious layer of poly(DMA) onthe surface of the contact lens, according to an aspect of the presentdisclosure.

FIG. 14 shows a scheme for the process of thermal initiatedpolymerization which can provide a thin lubricious layer of poly(DMA) onthe surface of the contact lens, according to an aspect of the presentdisclosure.

FIGS. 15A and 15B show representative photographs of water contact usedfor contact angle measurement of ACUVUE® Advanced lens with (FIG. 15A)and without (FIG. 15B) thermally initiated modification to provide alubricious contact lens, according to an aspect of the presentdisclosure.

FIG. 16 shows a scheme for the process of photochemically initiatedpolymerization which can provide a thin lubricious layer of poly(DMA) onthe surface of the contact lens, according to an aspect of the presentdisclosure.

FIGS. 17A and 17B show representative photographs of water contact usedfor contact angle measurement of ACUVUE® Oasys lens with (FIG. 17A) andwithout (FIG. 17B) photochemically initiated modification to provide alubricious contact lens, according to an aspect of the presentdisclosure.

FIG. 18 shows representative friction coefficient data for an unmodifiedACUVUE® TruEye® contact lens and an ACUVUE® TruEye® contact lensmodified using 40 wt % DMA, 30 wt % TEMED and 3 wt % APS (reaction time15 seconds) according to aspects of the disclosed compositions andmethods.

FIG. 19 shows representative data for water content versus concentrationof DMA for an ACUVUE® Advance contact lens modified to have a poly(DMA)lubricious coating, according to an aspect of the present disclosure,made using 3.4 wt % AIBN and reaction at 70° C. for 12 hours and whereDMA concentration was varied as indicated.

FIG. 20 shows representative data for mass of the wet layer versusconcentration of DMA for an ACUVUE® Advance contact lens modified tohave a poly(DMA) lubricious coating, according to an aspect of thepresent disclosure, made using 3.4 wt % AIBN and reaction at 70° C. for12 hours and where DMA concentration was varied as indicated.

FIG. 21 shows representative data for mass of the dried layer versusconcentration of DMA for an ACUVUE® Advance contact lens modified tohave a poly(DMA) lubricious coating, according to an aspect of thepresent disclosure, made using 3.4 wt % AIBN and reaction at 70° C. for12 hours and where DMA concentration was varied as indicated.

FIG. 22 shows representative data for water content versus concentrationof AIBN for an ACUVUE® Advance contact lens modified to have a poly(DMA)lubricious coating, according to an aspect of the present disclosure,made using 4 wt % DMA and reaction at 70° C. for 12 hours and where AIBNconcentration was varied as indicated.

FIG. 23 shows representative data for mass of the wet layer versusconcentration of AIBN for an ACUVUE® Advance contact lens modified tohave a poly(DMA) lubricious coating, according to an aspect of thepresent disclosure, made using 4 wt % DMA and reaction at 70° C. for 12hours and where AIBN concentration was varied as indicated.

FIG. 24 shows representative data for mass of the dried layer versusconcentration of AIBN for an ACUVUE® Advance contact lens modified tohave a poly(DMA) lubricious coating, according to an aspect of thepresent disclosure, made using 4 wt % DMA and reaction at 70° C. for 12hours and where AIBN concentration was varied as indicated.

FIG. 25 shows representative data for water content versus reaction timefor an ACUVUE® Advance contact lens modified to have a poly(DMA)lubricious coating, according to an aspect of the present disclosure,made using 4 wt % DMA and 3.4 wt % AIBN, and where reaction time wasvaried as indicated.

FIG. 26 shows representative data for mass of the wet layer versusreaction time for an ACUVUE® Advance contact lens modified to have apoly(DMA) lubricious coating, according to an aspect of the presentdisclosure, made using 4 wt % DMA and 3.4 wt % AIBN, and where reactiontime was varied as indicated.

FIG. 27 shows representative data for mass of the dried layer versusreaction time for an ACUVUE® Advance contact lens modified to have apoly(DMA) lubricious coating, according to an aspect of the presentdisclosure, made using 4 wt % DMA and 3.4 wt % AIBN, and where reactiontime was varied as indicated.

FIG. 28 shows representative contact angle data versus concentration ofDMA for an ACUVUE® Advance contact lens modified to have a poly(DMA)lubricious coating, according to an aspect of the present disclosure,made using 3.4 wt % AIBN and reaction at 70° C. for 12 hours and whereDMA concentration was varied as indicated.

FIG. 29 shows representative contact angle data versus concentration ofAIBN for an ACUVUE® Advance contact lens modified to have a poly(DMA)lubricious coating, according to an aspect of the present disclosure,made using 4 wt % DMA and reaction at 70° C. for 12 hours and where AIBNconcentration was varied as indicated.

FIG. 30 shows representative contact angle data versus concentration ofAIBN for an ACUVUE® Advance contact lens modified to have a poly(DMA)lubricious coating, according to an aspect of the present disclosure,made using 4 wt % DMA and 3.4 wt % AIBN, and where reaction time wasvaried as indicated.

FIG. 31 shows representative data for an ACUVUE® Advance contact lensmodified to have a lubricious coating, according to an aspect of thepresent disclosure, made using the indicated AIBN and DMAconcentrations. A representative photograph image is shown for eachreaction condition along with a summary of lubricity and shapecharacteristics following modification with the lubricious coating.Reactions were carried out at 70° C. for 12 hours.

FIG. 32 shows representative stacked FTIR spectra for pure poly(DMA) andan untreated ACUVUE® Advance contact lens as indicated, and also for anACUVUE® Advance contact lens modified using the indicated DMAconcentrations in the presence of 3.4 wt % AIBN and reaction at 70° C.for 12 hours, according to an aspect of the present disclosure. The purepoly(DMA) sample used for comparison was prepared as described hereinbelow in the Examples.

FIG. 33 shows representative stacked FTIR spectra for pure poly(DMA) andan untreated ACUVUE® Advance contact lens as indicated, and also for anACUVUE® Advance contact lens modified using the indicated AIBNconcentrations in the presence of 4 wt % DMA and reaction at 70° C. for12 hours, according to an aspect of the present disclosure.

FIG. 34 shows representative stacked FTIR spectra for pure poly(DMA) andan untreated ACUVUE® Advance contact lens as indicated, and also for anACUVUE® Advance contact lens modified using 3.4 wt % AIBN and 4 wt % DMAand reaction at 70° C. for the indicated reaction times, according to anaspect of the present disclosure.

FIG. 35 shows representative friction coefficient data for an unmodifiedACUVUE® Advance contact lens and an ACUVUE® Advance contact lensmodified using 4 wt % DMA and 3.4 wt % AIBN, and reaction at 70° C. for12 hours, according to aspects of the disclosed compositions andmethods.

FIG. 36 shows representative data for the release of AIBN versus timefrom the indicated commercially available contact lens. Briefly, theindicated contact lens was soaked in a methanol solution of 3.4 wt %AIBN for 24 hours. The contact lens was then transferred to deionizedwater at 80° C. and samples of the water were analyzed using UV-visspectrophotometry to determine the dynamic concentration of the AIBNthat had been released from the contact lens.

FIG. 37 shows representative data for the release of AIBN versus timefrom the indicated commercially available contact lens. Briefly, theindicated contact lens was soaked in a methanol solution of 1.8 wt %vitamin E and 7 wt % AIBN for 24 hours. The contact lens was thentransferred to deionized water at 80° C. and samples of the water wereanalyzed using UV-vis spectrophotometry to determine the dynamicconcentration of the AIBN that had been released from the contact lens.

FIG. 38 shows representative friction coefficient data for an unmodifiedACUVUE® Oasys contact lens and an ACUVUE® Oasys contact lens modifiedper disclosed methods. Briefly, a ACUVUE® Oasys contact lens was infusedusing a solution comprising 1.8 wt % vitamin E and 7 wt % AIBN, and thenpolymerized by placing the lens in a 4 wt % DMA solution and thereaction carried out at 80° C. for 12 hours, according to aspects of thedisclosed compositions and methods.

FIG. 39 shows representative images of an unmodified ACUVUE® Oasyscontact lens (contact lens on left) and an ACUVUE® Oasys contact lensmodified as described for FIG. 38 (contact lens on right), according toaspects of the disclosed compositions and methods.

FIG. 40 shows representative data for the indicated contact lensmodified to have a lubricious coating, according to an aspect of thepresent disclosure, made using 3.4 wt % AIBN and 30 wt % DMAconcentrations. A representative photograph image is shown for eachreaction condition along with a summary of lubricity and shapecharacteristics following modification with the lubricious coating.Reactions were carried out under UV light for 20 seconds using an RC-742Pulsed UV System (Xenon Corporation, Wilmington, Massachussetts).

FIG. 41 shows representative data for the indicated contact lensmodified to have a lubricious coating, according to an aspect of thepresent disclosure, made using 3.4 wt % AIBN and 40 wt % DMAconcentrations. A representative photograph image is shown for eachreaction condition along with a summary of lubricity and shapecharacteristics following modification with the lubricious coating.Reactions were carried out under UV light for 20 seconds using an RC-742Pulsed UV System.

FIG. 42 shows representative data for an ACUVUE® Oasys contact lensmodified to have a lubricious coating, according to an aspect of thepresent disclosure, made using the indicated AIBN concentrations with 40wt % DMA. A representative photograph image is shown for each reactioncondition along with a summary of lubricity and shape characteristicsfollowing modification with the lubricious coating. Reactions werecarried out by UV irradiation for 20 seconds using an RC-742 Pulsed UVSystem.

FIG. 43 shows representative friction coefficient data for an unmodifiedACUVUE® Oasys contact lens and an ACUVUE® Oasys contact lens modifiedusing 40 wt % DMA and 3 wt % AIBN, and reaction carried using UVirradiation for 20 seconds using an RC-742 Pulsed UV System, accordingto aspects of the disclosed compositions and methods.

FIGS. 44A-44D shows representative aspects of a testing device used todetermine friction coefficient between a contact lens and a rabbitcadaver cornea. FIG. 44A shows the overall testing device with the chuckand forked tongue highlighted by the indicated arrows.

FIG. 44B shows a closer view of the chuck and forked tongue shown inFIG. 44A. FIG. 44C shows a domed rod with a rabbit cadaver corneaattached to the domed rod. FIG. 44D shows a concaved rod with a testcontact lens attached to the concaved rod.

FIG. 45 shows representative torque test data obtained for a commercialcontact lens (ACUVUE® 2 contact lens) in the device shown in FIGS.44A-44D.

FIG. 46 shows representative friction coefficient data determined atdifferent angular frequencies. The test lens was an unmodified ACUVUE®TruEye® lens.

FIG. 47 shows representative friction coefficient data determined atdifferent angular frequencies. The test lens was an ACUVUE® TruEye®lens, according to an aspect of the present disclosure, modified using40 wt % DMA, 30 wt % TEMED and 3 wt % APS with oxygen exposure toterminate the polymerization.

Additional advantages of the present disclosure will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or can be learned by practice of the presentdisclosure. The advantages of the present disclosure will be realizedand attained by means of the elements and combinations particularlypointed out in the appended claims. It is to be understood that both theforegoing general description and the following detailed description areexemplary and explanatory only and are not restrictive of the presentdisclosure, as claimed.

DETAILED DESCRIPTION

Many modifications and other aspects disclosed herein will come to mindto one skilled in the art to which the disclosed compositions andmethods pertain having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the present disclosures are not to be limited to thespecific aspects disclosed and that modifications and other aspects areintended to be included within the scope of the appended claims. Theskilled artisan will recognize many variants and adaptations of theaspects described herein. These variants and adaptations are intended tobe included in the teachings of this disclosure and to be encompassed bythe claims herein.

Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual aspects described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalaspects without departing from the scope or spirit of the presentdisclosure.

Any recited method can be carried out in the order of events recited orin any other order that is logically possible. That is, unless otherwiseexpressly stated, it is in no way intended that any method or aspect setforth herein be construed as requiring that its steps be performed in aspecific order. Accordingly, where a method claim does not specificallystate in the claims or descriptions that the steps are to be limited toa specific order, it is no way intended that an order be inferred, inany respect. This holds for any possible non-express basis forinterpretation, including matters of logic with respect to arrangementof steps or operational flow, plain meaning derived from grammaticalorganization or punctuation, or the number or type of aspects describedin the specification.

All publications mentioned herein are incorporated herein by referenceto disclose and describe the methods and/or materials in connection withwhich the publications are cited. The publications discussed herein areprovided solely for their disclosure prior to the filing date of thepresent application. Nothing herein is to be construed as an admissionthat the present disclosure is not entitled to antedate such publicationby virtue of prior disclosure. Further, the dates of publicationprovided herein can be different from the actual publication dates,which can require independent confirmation.

While aspects of the present disclosure can be described and claimed ina particular statutory class, such as the system statutory class, thisis for convenience only and one of skill in the art will understand thateach aspect of the present disclosure can be described and claimed inany statutory class.

It is also to be understood that the terminology used herein is for thepurpose of describing particular aspects only and is not intended to belimiting. Unless defined otherwise, all technical and scientific termsused herein have the same meaning as commonly understood by one ofordinary skill in the art to which the disclosed compositions andmethods belong. It will be further understood that terms, such as thosedefined in commonly used dictionaries, should be interpreted as having ameaning that is consistent with their meaning in the context of thespecification and relevant art and should not be interpreted in anidealized or overly formal sense unless expressly defined herein.

Prior to describing the various aspects of the present disclosure, thefollowing definitions are provided and should be used unless otherwiseindicated. Additional terms may be defined elsewhere in the presentdisclosure.

A. DEFINITIONS

As used herein, “comprising” is to be interpreted as specifying thepresence of the stated features, integers, steps, or components asreferred to, but does not preclude the presence or addition of one ormore features, integers, steps, or components, or groups thereof.Moreover, each of the terms “by”, “comprising,” “comprises”, “comprisedof,” “including,” “includes,” “included,” “involving,” “involves,”“involved,” and “such as” are used in their open, non-limiting sense andmay be used interchangeably. Further, the term “comprising” is intendedto include examples and aspects encompassed by the terms “consistingessentially of” and “consisting of.” Similarly, the term “consistingessentially of” is intended to include examples encompassed by the term“consisting of.

As used in the specification and the appended claims, the singular forms“a,” “an” and “the” include plural referents unless the context clearlydictates otherwise. Thus, for example, reference to “a monomer,” “alens,” or “an initiator,” includes, but is not limited to, two or moresuch monomers, lenses, or initiators, and the like.

Reference to “a” chemical compound refers one or more molecules of thechemical compound, rather than being limited to a single molecule of thechemical compound. Furthermore, the one or more molecules may or may notbe identical, so long as they fall under the category of the chemicalcompound. Thus, for example, “a” poly(DMA) is interpreted to include oneor more polymer molecules of the poly(dimethyl acrylamide), where thepolymer molecules may or may not be identical (e.g., different molecularweights and/or isomers).

It should be noted that ratios, concentrations, amounts, and othernumerical data can be expressed herein in a range format. It will befurther understood that the endpoints of each of the ranges aresignificant both in relation to the other endpoint, and independently ofthe other endpoint. It is also understood that there are a number ofvalues disclosed herein, and that each value is also herein disclosed as“about” that particular value in addition to the value itself. Forexample, if the value “10” is disclosed, then “about 10” is alsodisclosed. Ranges can be expressed herein as from “about” one particularvalue, and/or to “about” another particular value. Similarly, whenvalues are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms a furtheraspect. For example, if the value “about 10” is disclosed, then “10” isalso disclosed.

When a range is expressed, a further aspect includes from the oneparticular value and/or to the other particular value. For example,where the stated range includes one or both of the limits, rangesexcluding either or both of those included limits are also included inthe present disclosure, e.g. the phrase “x to y” includes the range from‘x’ to ‘y’ as well as the range greater than ‘x’ and less than ‘y’. Therange can also be expressed as an upper limit, e.g. ‘about x, y, z, orless’ and should be interpreted to include the specific ranges of ‘aboutx’, ‘about y’, and ‘about z’ as well as the ranges of ‘less than x’,less than y’, and ‘less than z’. Likewise, the phrase ‘about x, y, z, orgreater’ should be interpreted to include the specific ranges of ‘aboutx’, ‘about y’, and ‘about z’ as well as the ranges of ‘greater than x’,greater than y’, and ‘greater than z’. In addition, the phrase “about‘x’ to ‘y’”, where ‘x’ and ‘y’ are numerical values, includes “about ‘x’to about ‘y’”.

It is to be understood that such a range format is used for convenienceand brevity, and thus, should be interpreted in a flexible manner toinclude not only the numerical values explicitly recited as the limitsof the range, but also to include all the individual numerical values orsub-ranges encompassed within that range as if each numerical value andsub-range is explicitly recited. To illustrate, a numerical range of“about 0.1% to 5%” should be interpreted to include not only theexplicitly recited values of about 0.1% to about 5%, but also includeindividual values (e.g., about 1%, about 2%, about 3%, and about 4%) andthe sub-ranges (e.g., about 0.5% to about 1.1%; about 5% to about 2.4%;about 0.5% to about 3.2%, and about 0.5% to about 4.4%, and otherpossible sub-ranges) within the indicated range.

As used herein, the terms “about,” “approximate,” “at or about,” and“substantially” mean that the amount or value in question can be theexact value or a value that provides equivalent results or effects asrecited in the claims or taught herein. That is, it is understood thatamounts, sizes, formulations, parameters, and other quantities andcharacteristics are not and need not be exact, but may be approximateand/or larger or smaller, as desired, reflecting tolerances, conversionfactors, rounding off, measurement error and the like, and other factorsknown to those of skill in the art such that equivalent results oreffects are obtained. In some circumstances, the value that providesequivalent results or effects cannot be reasonably determined. In suchcases, it is generally understood, as used herein, that “about” and “ator about” mean the nominal value indicated ±10% variation unlessotherwise indicated or inferred. In general, an amount, size,formulation, parameter or other quantity or characteristic is “about,”“approximate,” or “at or about” whether or not expressly stated to besuch. It is understood that where “about,” “approximate,” or “at orabout” is used before a quantitative value, the parameter also includesthe specific quantitative value itself, unless specifically statedotherwise.

As used herein, the term “effective amount” refers to an amount that issufficient to achieve the desired modification of a physical property ofthe composition or material. For example, an “effective amount” of a DMAin a solution refers to an amount that is sufficient to achieve thedesired improvement in the property modulated by the formulationcomponent, e.g. a lubricious surface layer on a contact lens comprisinga polymer derived from DMA. The specific level in terms of wt % in acomposition required as an effective amount will depend upon a varietyof factors including the amount and type of monomer, amount and type ofinitiator, type of contact lens being modified by the disclosed method,and desired level of lubricity.

The term “contacting” as used herein refers to bringing a disclosedmonomer and/or initiator in proximity to a contact lens in such a mannerthat the disclosed monomer and/or initiator can interact chemicallyand/or physically with the component contacted, e.g., a contact lenssurface.

As used herein, the term “attached” can refer to covalent ornon-covalent interaction between two or more molecules. Non-covalentinteractions can include ionic bonds, electrostatic interactions, vander Walls forces, dipole-dipole interactions, dipole-induced-dipoleinteractions, London dispersion forces, hydrogen bonding, halogenbonding, electromagnetic interactions, π-π interactions, cation-πinteractions, anion-π interactions, polar π-interactions, andhydrophobic effects. For example, if a disclosed surface layer isattached to a contact lens surface, it can comprise covalent ornon-covalent interactions between the surface layer molecules, e.g., apoly(dimethyl acrylamide) molecule, and one or more molecules that formthe contact lens.

As used herein, the term “contact lens” refers to a structure that canbe placed on or within a wearer's eye. A contact lens can correct,improve, or alter a user's eyesight, but that need not be the case. Acontact lens can be of any appropriate material known in the art orlater developed, and can be a soft lens, a hard lens, or a hybrid lens.A “hydrogel contact lens” refers to a contact lens comprising a hydrogelmaterial. A “silicone hydrogel contact lens” refers to a contact lenscomprising a silicone hydrogel material.

As used herein, the term “surface layer” in reference to a contact lensmeans a layer of a material which is the outmost layer on the contactlens and includes the surface of the contact lens. The surface layerneed not be limited to interaction with the contact lens only at thesurface, but can comprise penetration into the lens to a limited degree.

As used herein, the term “hydrogel” or “hydrogel material” refers to apolymeric material which can absorb at least 10 percent by weight ofwater when it is fully hydrated. A hydrogel comprises a threedimensional network of polymers that are crosslinked to formwater-swellable but water-insoluble structures. The term hydrogel is tobe applied to polymers in a dry state (xerogel), as well as in a wetstate.

As used herein, the term “silicone hydrogel” refers to asilicone-containing hydrogel obtained by copolymerization of apolymerizable composition comprising at least one silicone-containingmonomer or at least one silicone-containing macromer or at least onecrosslinkable silicone-containing prepolymer which can absorb at least10 percent by weight of water when it is fully hydrated.

As used herein, the term “hydrophilic” refers a material or portionthereof that will more readily associate with water than with lipids.

As used herein, the term “polymer” means a material formed bypolymerizing one or more monomers.

As used herein, the term “polyacrylamide”, refers to a polymercomprising residues derived from acrylamide monomers.

As used herein, the term “thermal initiator” refers to a chemical thatinitiates radical crosslinking/polymerizing reaction in the presence ofthermal energy. The thermal energy may be from a heat source or frommicrowave irradiation. Examples of suitable thermal initiators include,but are not limited to, 2,2′-azobis(2,4-dimethylpentanenitrile),2,2′-azobis(2-methylpropanenitrile), 2,2′-azobis(2-methylbutanenitrile),peroxides such as benzoyl peroxide, and the like.

As used herein, the terms “DMA,” “N,N-dimethylacrylamide,” and“dimethylacrylamide” can be used interchangeably and refer to a chemicalcompound that act as a monomer in a chemical reaction forming a polymercomprising residues derived from DMA monomer units.

As used herein, the terms “poly(DMA),” “poly(DMA),” and “poly(dimethylacrylamide)” can be used interchangeably and refer to a homopolymercomprising residues derived from DMA.

As used herein, the term “units” can be used to refer to individualmonomer units such that, for example, DMA repeat units refers toindividual DMA monomer units in a polymer. It is understood that “unit”and “residue derived from a monomer” can be used interchangeably.

As used herein, the term “water contact angle” refers to a water contactangle (measured by the method disclosed herein below), which is obtainedby averaging measurements of at least 3 individual contact lenses.

As used herein, the terms “optional” or “optionally” means that thesubsequently described event or circumstance can or cannot occur, andthat the description includes instances where said event or circumstanceoccurs and instances where it does not.

Unless otherwise specified, temperatures referred to herein are based onatmospheric pressure (i.e. one atmosphere).

Disclosed are the components to be used to prepare the compositions ofthe disclosure as well as the compositions themselves to be used withinthe methods disclosed herein. These and other materials are disclosedherein, and it is understood that when combinations, subsets,interactions, groups, etc. of these materials are disclosed that whilespecific reference of each various individual and collectivecombinations and permutation of these compounds cannot be explicitlydisclosed, each is specifically contemplated and described herein. Forexample, if a particular compound is disclosed and discussed and anumber of modifications that can be made to a number of moleculesincluding the compounds are discussed, specifically contemplated is eachand every combination and permutation of the compound and themodifications that are possible unless specifically indicated to thecontrary. Thus, if a class of molecules A, B, and C are disclosed aswell as a class of molecules D, E, and F and an example of a combinationmolecule, A-D is disclosed, then even if each is not individuallyrecited each is individually and collectively contemplated meaningcombinations, A-E, A-F, B-D, B-E, B-F, C-D, C-E, and C-F are considereddisclosed. Likewise, any subset or combination of these is alsodisclosed. Thus, for example, the sub-group of A-E, B-F, and C-E wouldbe considered disclosed. This concept applies to all aspects of thisapplication including, but not limited to, steps in methods of makingand using the compositions of the disclosure. Thus, if there are avariety of additional steps that can be performed it is understood thateach of these additional steps can be performed with any specific aspector combination of aspects of the methods of the disclosure.

References in the specification and concluding claims to parts by weightof a particular element or component in a composition or article,denotes the weight relationship between the element or component and anyother elements or components in the composition or article for which apart by weight is expressed. Thus, in a compound containing 2 parts byweight of component X and 5 parts by weight component Y, X and Y arepresent at a weight ratio of 2:5, and are present in such ratioregardless of whether additional components are contained in thecompound.

As used herein the terms “weight percent,” “wt %,” and “wt. %,” whichcan be used interchangeably, indicate the percent by weight of a givencomponent based on the total weight of the composition, unless otherwisespecified. That is, unless otherwise specified, all wt % values arebased on the total weight of the composition. It should be understoodthat the sum of wt % values for all components in a disclosedcomposition or formulation are equal to 100.

Before proceeding to the Examples, it is to be understood that thisdisclosure is not limited to particular aspects described, and as suchmay, of course, vary. Other systems, methods, features, and advantagesof foam compositions and components thereof will be or become apparentto one with skill in the art upon examination of the following drawingsand detailed description. It is intended that all such additionalsystems, methods, features, and advantages be included within thisdescription, be within the scope of the present disclosure, and beprotected by the accompanying claims. It is also to be understood thatthe terminology used herein is for the purpose of describing particularaspects only, and is not intended to be limiting. The skilled artisanwill recognize many variants and adaptations of the aspects describedherein. These variants and adaptations are intended to be included inthe teachings of this disclosure and to be encompassed by the claimsherein.

B. CONTACT LENS COMPRISING A LUBRICIOUS SURFACE LAYER

In one aspect, the present disclosure relates to a contact lenscomprising a disclosed lubricious surface layer. In a further aspect,the lubricious surface layer comprises a polyacrylamide, e.g., apoly(N,N-dimethylacrylamide. In various aspects, the lubricious surfacelayer is formed at the surface of a contact lens. In other aspects, thelubricious coatings are formed at the surface and near the surface of acontact lens, but within the edge region of the contact lens. In afurther aspect, the contact lens can be a hydrogel lens. In a furtheraspect, the contact lens can be a silicone hydrogel lens.

In various aspects, the present disclosure is directed to a contact lenscomprising a surface layer comprising polyacrylamide, such that thesurface layer is attached to a surface of a contact lens. In someaspects, the surface layer is attached via one or more covalent linkagesbetween one or more molecules of the surface layer, e.g., apolyacrylamide, and one or more molecules in the contact lens, e.g., ahydrogel or silicone hydrogel molecule or polymer used to fabricate thecontact lens. In further aspects, one or more covalent linkages betweenone or more molecules of the surface layer, e.g., a polyacrylamide, andone or more molecules in the contact lens and/or non-covalentinteractions between one or more molecules of the surface layer, e.g., apolyacrylamide, and one or more molecules in the contact lens. In someaspects, one or more molecules of the surface layer, e.g., apolyacrylamide, are entangled with one another and form a mat, mesh, orother entangled molecular structure, and that the one or more entangledmolecules of the surface layer form covalent and/or non-covalentinteractions with molecules in the contact lens.

In various aspects, the polyacrylamide is a homopolymer. In a furtheraspect, the polyacrylamide is formed from monomers such as, but notlimited to, substituted or unsubstituted N,N-dimethyl (meth)acrylamide(alternatively referred to as “N,N-dimethylmethylacrylamide”),N,N-dimethylacrylamide (DMA), methacrylamide, N-methylmethacrylamide,N-(2-hydroxyethyl)methacrylamide, 2-acrylamidoglycolic acid,3-acryloylamino-1-propanol, N-hydroxyethyl acrylamide,N⁴tris(hydroxymethyl)methyl]-acrylamide.

In a further aspect, the polyacrylamide is formed from monomers such as,but not limited to, acrylamide; methacrylamide; N-alkylacrylamides suchas N-ethylacrylamide, N-isopropylacrylamide or N-tert-butylacrylamide;N-alkylmethacrylamides such as N-ethylmethacrylamide orN-isopropylmethacrylamide; N,N-dialkylacrylamides such asN,N-dimethylacrylamide and N,N-diethyl-acrylamide;N-[(dialkylamino)alkyl]acrylamides such asN-[3dimethylamino)propyl]acrylamide orN-[3-(diethylamino)propyl]acrylamide;N-[(dialkylamino)alkyl]methacrylamides such asN-[3-dimethylamino)propyl]methacrylamide orN-[3-(diethylamino)propyl]methacrylamide.

In various aspects, the polyacrylamide is a copolymer of acrylamideformed from at least two different monomers selected from acrylamide;methacrylamide; N-alkylacrylamides such as N-ethylacrylamide,N-isopropylacrylamide or N-tert-butylacrylamide; N-alkylmethacrylamidessuch as N-ethylmethacrylamide or N-isopropylmethacrylamide;N,N-dialkylacrylamides such as N,N-dimethylacrylamide andN,N-diethyl-acrylamide; N-[(dialkylamino)alkyl]acrylamides such asN-[3dimethylamino)propyl]acrylamide orN-[3-(diethylamino)propyl]acrylamide;N-[(dialkylamino)alkyl]methacrylamides such asN-[3-dimethylamino)propyl]methacrylamide orN-[3-(diethylamino)propyl]methacrylamide.

In some aspects, the polyacrylamide is a homopolymer that ispoly(N,N-dimethylacrylamide), i.e., a polymer formed fromN,N-dimethylacrylamide monomers.

In various aspects, the polyacrylamide in the surface layer has anaverage molecular weight of about 1 kDa to about 5,000 kDa; about 10 kDato about 5,000 kDa; about 100 kDa to about 5,000 kDa; about 1,000 kDa toabout 5,000 kDa; about 10 kDa to about 4,000 kDa; about 10 kDa to about3,000 kDa; about 10 kDa to about 2,000 kDa; about 10 kDa to about 1,000kDa; about 100 kDa to about 4,000 kDa; about 100 kDa to about 3,000 kDa;about 100 kDa to about 2,000 kDa; about 100 kDa to about 1,000 kDa; asub-range within any of the foregoing ranges; or a value within any ofthe foregoing ranges.

In a further aspect, the polyacrylamide in the surface layer has anaverage molecular weight of about 1 kDa to about 1,000 kDa; 1 kDa toabout 100 kDa; 1 kDa to about 10 kDa; a sub-range within any of theforegoing ranges; or a value within any of the foregoing ranges.

In various aspects, the surface layer has a thickness that is from about0.1 μm to about 5 μm. In a further aspect, the surface layer has athickness that is from about 1 μm to about 5 μm. In a still furtheraspect, the surface layer has a thickness that is from about 2 μm toabout 5 μm. In a yet further aspect, the surface layer has a thicknessthat is from about 31 μm to about 5 μm. In an even further aspect, thesurface layer has a thickness that is from about 4 μm to about 5 μm. Ina further aspect, the surface layer has a thickness that is from about 1μm to about 4 μm. In a still further aspect, the surface layer has athickness that is from about 1 μm to about 3 μm. In a yet furtheraspect, the surface layer has a thickness that is from about 1 μm toabout 2 μm. In an even further aspect, the surface layer has a thicknessthat is from about 0.1 μm to about 2 μm. In a further aspect, thesurface layer has a thickness that is from about 0.1 μm to about 1 μm.

In various aspects, the surface layer has a thickness that is about 0.1μm, about 0.2 μm, about 0.3 μm, about 0.4 μm, about 0.5 μm, about 0.6μm, about 0.7 μm, about 0.8 μm, about 0.9 μm, about 1.0 μm, about 1.1μm, about 1.2 μm, about 1.3 μm, about 1.4 μm, about 1.5 μm, about 1.6μm, about 1.7 μm, about 1.8 μm, about 1.9 μm, about 2.0 μm, about 2.1μm, about 2.2 μm, about 2.3 μm, about 2.4 μm, about 2.5 μm, about 2.6μm, about 2.7 μm, about 2.8 μm, about 2.9 μm, about 3.0 μm, about 3.1μm, about 3.2 μm, about 3.3 μm, about 3.4 μm, about 3.5 μm, about 3.6μm, about 3.7 μm, about 3.8 μm, about 3.9 μm, about 4.0 μm, about 4.1μm, about 4.2 μm, about 4.3 μm, about 4.4 μm, about 4.5 μm, about 4.6μm, about 4.7 μm, about 4.8 μm, about 4.9 μm, about 5.0 μm; any rangeencompassed by one or more of the foregoing values; or any combinationof the foregoing values.

In various aspects, a contact lens comprising a disclosed lubricioussurface layer has an increased water content of about 0.5 wt % to about75 wt % compared to the same contact lens without the disclosedlubricious surface layer. In a further aspect, a contact lens comprisinga disclosed lubricious surface layer has an increased water content ofcompared to the same contact lens without the disclosed lubricioussurface layer, and wherein the increase in water content is about 1 wt%, about 2 wt %, about 3 wt %, about 4 wt %, about 5 wt %, about 6 wt %,about 7 wt %, about 8 wt %, about 9 wt %, about 10 wt %, about 11 wt %,about 12 wt %, about 13 wt %, about 14 wt %, about 15 wt %, about 16 wt%, about 17 wt %, about 18 wt %, about 19 wt %, about 20 wt %, about 21wt %, about 22 wt %, about 23 wt %, about 24 wt %, about 25 wt %, about26 wt %, about 27 wt %, about 28 wt %, about 29 wt %, about 30 wt %,about 31 wt %, about 32 wt %, about 33 wt %, about 34 wt %, about 35 wt%, about 36 wt %, about 37 wt %, about 38 wt %, about 39 wt %, about 40wt %, about 41 wt %, about 42 wt %, about 43 wt %, about 44 wt %, about45 wt %, about 46 wt %, about 47 wt %, about 48 wt %, about 49 wt %,about 50 wt %, about 51 wt %, about 52 wt %, about 53 wt %, about 54 wt%, about 55 wt %, about 56 wt %, about 57 wt %, about 58 wt %, about 59wt %, about 60 wt %, about 61 wt %, about 62 wt %, about 63 wt %, about64 wt %, about 65 wt %, about 66 wt %, about 67 wt %, about 68 wt %,about 69 wt %, about 70 wt %, about 71 wt %, about 72 wt %, about 73 wt%, about 74 wt %, about 75 wt %; any range encompassed by one or more ofthe foregoing values; or any combination of the foregoing values.

In various aspects, a disclosed lubricious surface layer has a watercontent of about 100 wt % to about 500 wt %; 200 wt % to about 500 wt %;300 wt % to about 500 wt %; 400 wt % to about 500 wt %; about 100 wt %to about 400 wt %; about 100 wt % to about 300 wt %; about 100 wt % toabout 200 wt %; a sub-range within any of the foregoing ranges; or avalue or combination of values within any of the foregoing ranges.

In various aspects, a contact lens comprising a disclosed lubricioussurface layer can have a water contact angle of from about 15 degrees toabout 60 degrees; about 20 degrees to about 60 degrees; about 25 degreesto about 60 degrees; about 30 degrees to about 60 degrees; about 35degrees to about 60 degrees; about 40 degrees to about 60 degrees; about45 degrees to about 60 degrees; a sub-range within any of the foregoingranges; or a value or combination of values within any of the foregoingranges.

In a further aspect, a contact lens comprising a disclosed lubricioussurface layer can have a water contact angle of from about 15 degrees toabout 50 degrees; about 15 degrees to about 45 degrees; about 15 degreesto about 40 degrees; about 15 degrees to about 35 degrees; about 15degrees to about 30 degrees; about 20 degrees to about 60 degrees; about20 degrees to about 50 degrees; about 20 degrees to about 45 degrees;about 20 degrees to about 40 degrees; about 20 degrees to about 35degrees; about 20 degrees to about 30 degrees; about 25 degrees to about60 degrees; about 25 degrees to about 50 degrees; about 25 degrees toabout 45 degrees; about 25 degrees to about 40 degrees; about 25 degreesto about 35 degrees; about 25 degrees to about 30 degrees; about 30degrees to about 60 degrees; about 30 degrees to about 50 degrees; about30 degrees to about 45 degrees; about 30 degrees to about 40 degrees;about 30 degrees to about 35 degrees; a sub-range within any of theforegoing ranges; or a value or combination of values within any of theforegoing ranges.

As stated herein above, the contact lens comprising a disclosedlubricious surface layer can be a hydrogel lens. In other furtheraspects, the contact lens can be a silicone hydrogel lens. A hydrogel ora silicone hydrogel is a hydrated crosslinked polymeric system thatcontains water in an equilibrium state. The physical properties ofhydrogels can vary widely and are mostly determined by their watercontent. Hydrogels can contain 10% to 90% water by weight and exhibitexcellent biocompatibility and as such are used for soft biomedicalapplications. In further aspects, hydrogels Hydrogels can contain 10% to90% water by weight

Accordingly, hydrogels are copolymers prepared from hydrophilicmonomers. In the case of silicone hydrogels, the hydrogel copolymers aregenerally prepared by polymerizing a mixture containing at least onedevice-forming silicone-containing monomer and at least onedevice-forming hydrophilic monomer. Either the silicone-containingmonomer or the hydrophilic monomer may function as a crosslinking agent(a crosslinking agent being defined as a monomer having multiplepolymerizable functionalities), or alternately, a separate crosslinkingagent may be employed in the initial monomer mixture from which thehydrogel copolymer is formed. (As used herein, the term “monomer” or“monomeric” and like terms denote relatively low molecular weightcompounds that are polymerizable by free radical polymerization, as wellas higher molecular weight compounds also referred to as “prepolymers”,“macromonomers”, and related terms.) Silicone hydrogels typically have awater content between about 10 to about 80 weight percent.

Examples of useful lens-forming hydrophilic monomers include: amidessuch as N,N-dimethylacrylamide and N,N-dimethylmethacrylamide; cycliclactams such as N-vinyl-2-pyrrolidone; (meth)acrylated alcohols, such as2-hydroxyethyl methacrylate and 2-hydroxyethylacrylate; and(meth)acrylated poly(ethyleneglycol)s; and azlactone-containingmonomers, such as 2-isopropenyl-4,4-dimethyl-2-oxazolin-5-one and2-vinyl-4,4-dimethyl-2-oxazolin-5-one. (As used herein, the term“(meth)” denotes an optional methyl substituent. Thus, terms such as“(meth)acrylate” denotes either methacrylate or acrylate, and“(meth)acrylic acid” denotes either methacrylic acid or acrylic acid.)Still further examples are the hydrophilic vinyl carbonate or vinylcarbamate monomers disclosed in U.S. Pat. No. 5,070,215, and thehydrophilic oxazolone monomers disclosed in U.S. Pat. No. 4,910,277, thedisclosures of which are incorporated herein by reference. Othersuitable hydrophilic monomers will be apparent to one skilled in theart.

As mentioned, one class hydrogel contact lens materials is siliconehydrogels. In this case, the initial lens-forming monomer mixturefurther comprises a silicone-containing monomer. Applicablesilicone-containing monomeric materials for use in the formation ofsilicone hydrogels are well known in the art and numerous examples areprovided in U.S. Pat. Nos. 4,136,250; 4,153,641; 4,740,533; 5,034,461;5,070,215; 5,260,000; 5,310,779; and 5,358,995.

In some aspects, a useful silicone hydrogel material, used to preparecontact lenses that can be used with the disclosed lubricious surfacelayers, comprises (based on the initial monomer mixture that iscopolymerized to form the hydrogel copolymeric material) 5 to 50percent, preferably 10 to 25, by weight of one or more siliconemacromonomers, 5 to 75 percent, preferably 30 to 60 percent, by weightof one or more polysiloxanylalkyl (meth)acrylic monomers, and 10 to 50percent, preferably 20 to 40 percent, by weight of a hydrophilicmonomer. In general, the silicone macromonomer is a poly(organosiloxane)capped with an unsaturated group at two or more ends of the molecule. Inaddition to the end groups in the above structural formulas, U.S. Pat.No. 4,153,641 to Deichert et al. discloses additional unsaturatedgroups, including acryloxy or methacryloxy. Fumarate-containingmaterials such as those taught in U.S. Pat. Nos. 5,512,205; 5,449,729;and 5,310,779 to Lai are also useful substrates in accordance with thedisclosure. Preferably, the silane macromonomer is a silicon-containingvinyl carbonate or vinyl carbamate or a polyurethane-polysiloxane havingone or more hard-soft-hard blocks and end-capped with a hydrophilicmonomer.

The hydrogel can be, but is not limited, to the contact lens materialclassified as Group I by U.S. FDA, i.e., nonionic polymers having a lowwater content (less than 50 wt %), such as Helfilcon A&B, Hioxifilcon B,Mafilcon, Polymacon, Tefilcon and Tetrafilcon A. Alternatively, thehydrogel can be, but is not limited, to the contact lens materialclassified as Group II by U.S. FDA, i.e., nonionic polymers having ahigh water content (greater than 50 wt %), such as Acofilcon A,Alfafilcon A, Hilafilcon B, Hioxifilcon A, Hioxifilcon B, Hioxifilcon D,Nelfilcon A, Nesofilcon A, Omafilcon A and Samfilcon A. Alternatively,the hydrogel can be but is not limited to the contact lens materialclassified as Group III by U.S. FDA, i.e., ionic polymers having a lowwater content (less than 50 wt %), such as Deltafilcon A. Alternatively,the hydrogel can be, but is not limited, to the contact lens materialclassified as Group IV by U.S. FDA, i.e., ionic polymers having a highwater content (greater than 50 wt %), such as Etafilcon A, Focofilcon A,Methafilcon A, Methafilcon B, Ocufilcon A, Ocufilcon B, Ocufilcon C,Ocufilcon D, Ocufilcon E, Phemfilcon A and Vifilcon A.

In further aspects, conventional hydrogel contact lenses, useful withthe disclosed lubricious surface layers, can be prepared by polymerizinga monomer mixture containing at least one hydrophilic monomer. The term“hydrophilic monomer” as used here denotes a monomer whose homopolymershave the ability to absorb water. The term is not intended to includemonomers merely because they have a hydrophilic group. A monomer is“hydrophilic” only if its homopolymer absorbs water. Specific examplesof hydrophilic monomers include methacrylamide, N-methylmethacrylamide,N,N-dimethylacrylamide, N,N-dimethylmethylacrylamide, glycerylmethacrylate, N-(2-hydroxyethyl)methacrylamide, N-methacryloyl glycine;(2-hydroxy-3-methacryloylpropyl)-4-methoxy phenylether; hydroxyethylmethacrylate, hydroxyethyl acrylate, acrylamide, methacrylamide,N,N-dimethylacrylamide, allyl alcohol, vinyl pyridine, vinylpyrrolidone, glycerol methacrylate, N-(1,1-dimethyl-3-oxobutyl)acrylamide, (meth)acrylic acid, hydroxy(C1-C6)alkylacrylates (such ashydroxethyl acrylate), hydroxy(C1-C6)alkylmethacrylates (such ashydroxyethyl methacrylate), and the like. In a further aspect, thecontact lens can comprise a hydrogel derived from common hydrogelmonomers such as, but not limited to, the following: lactic acid,glycolic acid, acrylic acid, 1-hydroxyethyl methacrylate, ethylmethacrylate, propylene glycol methacrylate, acrylamide,N-vinylpyrrolidone, methyl methacrylate, glycidyl methacrylate, glycolmethacrylate, ethylene glycol, fumaric acid, and the like. Common crosslinking agents include tetraethylene glycol dimethacrylate andN,N′-methylenebisacrylamide.

In various aspects, a contact lens comprising a disclosed lubricioussurface layer can be a preformed contact lenses. Preformed contactlenses suitable for modification to comprise a disclosed lubricioussurface layer can be produced in a conventional “spin-casting mold,” asdescribed for example in U.S. Pat. No. 3,408,429, or by the fullcast-molding process in a static form, as described in U.S. Pat. Nos.4,347,198; 5,508,317; 5,583,463; 5,789,464; and 5,849,810, or by lathecutting of buttons as used in making customized contact lenses. Incast-molding, a lens formulation typically is dispensed into molds andcured (i.e., polymerized and/or crosslinked) in molds for making contactlenses.

For production of preformed hydrogel contact lenses, a hydrogel lensformulation typically is: either (1) a monomer mixture comprising (a) atleast one hydrophilic vinylic monomer and (b) at least one componentselected from the group consisting of a vinylic crosslinking agent, ahydrophobic vinylic monomer, an internal wetting agent, a free-radicalinitiator (photoinitiator or thermal initiator), a UV-absorbing agent, avisibility tinting agent (e.g., dyes, pigments, or mixtures thereof),antimicrobial agents (e.g., preferably silver nanoparticles), abioactive agent, and combinations thereof; or (2) an aqueous solutioncomprising one or more water-soluble prepolymers and at least onecomponent selected from the group consisting of hydrophilic vinylicmonomer, a vinylic crosslinking agent, a hydrophobic vinylic monomer, aninternal wetting agent, a free-radical initiator (photoinitiator orthermal initiator), a UV-absorbing agent, a visibility tinting agent(e.g., dyes, pigments, or mixtures thereof), antimicrobial agents (e.g.,preferably silver nanoparticles), a bioactive agent, and combinationsthereof. Resultant preformed hydrogel contact lenses then can besubjected to extraction with an extraction solvent to removeunpolymerized components from the resultant lenses and to hydrationprocess, as known by a person skilled in the art. It is understood thatan internal wetting agent present in a hydrogel lens formulation canimprove the hydrophilicity (as measured by water-break-up-time, WBUT)and/or wettability (as measured by water contact angle, WCA) ofpreformed hydrogel contact lenses compared to those of control preformedhydrogel contact lenses obtained from a control hydrogel lensformulation without the internal wetting agent.

For production of preformed silicone hydrogel (SiHy) contact lenses, aSiHy lens formulation for cast-molding or spin-cast molding or formaking SiHy rods used in lathe-cutting of contact lenses generallycomprises at least one components selected from the group consisting ofa silicone-containing vinylic monomer, a silicone-containing vinylicmacromer, a silicone-containing prepolymer, a hydrophilic vinylicmonomer, a hydrophobic vinylic monomer, a vinylic crosslinking agent, afree-radical initiator (photoinitiator or thermal initiator), ahydrophilic vinylic macromer/prepolymer, and combination thereof, aswell known to a person skilled in the art. A SiHy contact lensformulation can also comprise other necessary components known to aperson skilled in the art, such as, for example, a UV-absorbing agent, avisibility tinting agent (e.g., dyes, pigments, or mixtures thereof),antimicrobial agents (e.g., preferably silver nanoparticles), abioactive agent, internal wetting agents, leachable tear-stabilizingagents, and mixtures thereof, as known to a person skilled in the art.Resultant preformed SiHy contact lenses then can be subjected toextraction with an extraction solvent to remove unpolymerized componentsfrom the resultant lenses and to hydration process, as known by a personskilled in the art. It is understood that an internal wetting agentpresent in a SiHy lens formulation can improve the hydrophilicity and/orwettability of preformed SiHy contact lenses compared to those ofcontrol preformed SiHy contact lenses obtained from a control SiHy lensformulation without the internal wetting agent.

Numerous SiHy lens formulations have been described in numerous patentsand patent applications published by the filing date of thisapplication. All of them can be used in obtaining a preformed SiHy lenswhich in turn becomes the inner layer of a SiHy contact lens of thedisclosure, so long as they will yield a SiHy material free of carboxylgroup(s). A Silly lens formulation for making commercial SiHy lenses,such as, lotrafilcon A, lotrafilcon B, balafilcon A, galyfilcon A,senofilcon A, narafilcon A, narafilcon B, comfilcon A, enfilcon A,asmofilcon A, somofilcon A, stenfilcon A, smafilcon A, smafilcon B,smafilcon C, enfilcon A, and efrofilcon A can also be used in makingpreformed SiHy contact lenses.

Any suitable hydrophilic vinylic monomers can be used in the disclosure.Examples of preferred hydrophilic vinylic monomers include withoutlimitation (meth)acrylamide, N,N-dimethyl (meth)acrylamide,2-acrylamidoglycolic acid, N-hydroxypropylacrylamide, N-hydroxyethylacrylamide, N-[tris(hydroxymethyl)methyl]-acrylamide,N-vinylpyrrolidone, N-vinyl formamide, N-vinyl acetamide, N-vinylisopropylamide, N-vinyl-N-methyl acetamide,N-methyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone,5-methyl-3-methylene-2-pyrrolidone, 2-hydroxyethylmethacrylate (HEMA),2-hydroxyethyl acrylate (HEA), hydroxypropyl acrylate, hydroxypropylmethacrylate (HPMA), trimethylammonium 2-hydroxy propylmethacrylate,N-2-aminoethyl (meth)acrylamide hydrochloride, N-3-aminopropyl(meth)acrylamide hydrochloride, aminoethyl methacrylate hydrochloride,aminopropyl methacrylate hydrochloride, dimethylaminoethyl methacrylate(DMAEMA), glycerol methacrylate (GMA), a C1-C4-alkoxy polyethyleneglycol (meth)acrylate having a weight average molecular weight of up to1500, (meth)acrylic acid, and mixtures thereof. Preferably, apolymerizable composition comprises at least about 25% by weight of oneor more hydrophilic vinylic monomers listed above.

Examples of water-soluble prepolymers include without limitation: awater-soluble crosslinkable poly(vinyl alcohol) prepolymer described inU.S. Pat. Nos. 5,583,163 and 6,303,687; a water-soluble vinylgroup-terminated polyurethane prepolymer described in U.S. Pat. No.6,995,192; derivatives of a polyvinyl alcohol, polyethyleneimine orpolyvinylamine, which are disclosed in U.S. Pat. No. 5,849,841; awater-soluble crosslinkable polyurea prepolymer described in U.S. Pat.Nos. 6,479,587 and 7,977,430; crosslinkable polyacrylamide;crosslinkable statistical copolymers of vinyl lactam, MMA and acomonomer, which are disclosed in U.S. Pat. No. 5,712,356; crosslinkablecopolymers of vinyl lactam, vinyl acetate and vinyl alcohol, which aredisclosed in U.S. Pat. No. 5,665,840; polyether-polyester copolymerswith crosslinkable side chains which are disclosed in U.S. Pat. No.6,492,478; branched polyalkylene glycol-urethane prepolymers disclosedin U.S. Pat. No. 6,165,408; polyalkylene glycol-tetra(meth)acrylateprepolymers disclosed in U.S. Pat. No. 6,221,303; crosslinkablepolyallylamine gluconolactone prepolymers disclosed in U.S. Pat. No.6,472,489.

Examples of preferred vinylic crosslinking agents include withoutlimitation di-(meth)acrylate-terminated polyethylene glycol,di-(meth)acrylate-terminated polyoxyethylene-polyoxypropylene blockcopolymer, tetraethyleneglycol diacrylate, triethyleneglycol diacrylate,diethyleneglycol diacrylate, ethyleneglycol diacrylate,tetraethyleneglycol dimethacrylate, triethyleneglycol dimethacrylate,diethyleneglycol dimethacrylate, ethyleneglycol dimethacrylate,tetraethyleneglycol divinyl ether, triethyleneglycol divinyl ether,diethyleneglycol divinyl ether, ethyleneglycol divinyl ether,trimethylopropane trimethacrylate, pentaerythritol tetramethacrylate,bisphenol A dimethacrylate, vinyl methacrylate, ethylenediaminedimethyacrylamide, ethylenediamine diacrylamide, glyceroldimethacrylate, triallyl isocyanurate, triallyl cyanurate,allylmethacrylate, allylacrylate, N-allyl-methacrylamide,N-allyl-acrylamide,1,3-bis(methacrylamidopropyl)-1,1,3,3-tetrakis(trimethyl-siloxy)disiloxane,N,N′-methylenebisacrylamide, N,N′-methylenebismethacrylamide,N,N′-ethylenebisacrylamide, N,N′-ethylenebismethacrylamide,1,3-bis(N-methacrylamidopropyl)-1,1,3,3-tetrakis-(trimethylsiloxy)disiloxane,1,3-bis(methacrylamidobutyl)-1,1,3,3-tetrakis(trimethylsiloxy)-disiloxane,1,3-bis(acrylamidopropyl)-1,1,3,3-tetrakis(trimethylsiloxy)-disiloxane,1,3-bis(methacryloxyethylureidopropyl)-1,1,3,3-tetrakis(trimethylsiloxy)disiloxane,and combinations thereof. A preferred cross-linking agent isdi-(meth)acrylate-terminated polyethylene glycol,di-(meth)acrylate-terminated polyoxyethylene-polyoxypropylene blockcopolymer, tetra(ethyleneglycol) diacrylate, tri(ethyleneglycol)diacrylate, ethyleneglycol diacrylate, di(ethyleneglycol) diacrylate,methylenebisacrylamide, triallyl isocyanurate, allyl (meth)acrylate, ortriallyl cyanurate. The amount of a cross-linking agent used isexpressed in the weight content with respect to the total polymer and ispreferably in the range from about 0.05% to about 3% (more preferablyfrom about 0.1% to about 2%).

Examples of preferred hydrophobic vinylic monomers includemethylacrylate, ethyl-acrylate, propylacrylate, isopropylacrylate,cyclohexylacrylate, 2-ethylhexylacrylate, methylmethacrylate,ethylmethacrylate, propylmethacrylate, vinyl acetate, vinyl propionate,vinyl butyrate, vinyl valerate, styrene, chloroprene, vinyl chloride,vinylidene chloride, acrylonitrile, 1-butene, butadiene,methacrylonitrile, vinyl toluene, vinyl ethyl ether,perfluorohexylethyl-thio-carbonyl-aminoethyl-methacrylate, isobornylmethacrylate, trifluoroethyl methacrylate, hexafluoro-isopropylmethacrylate, hexafluorobutyl methacrylate.

C. METHODS OF PREPARING THE DISCLOSED LUBRICIOUS SURFACE LAYERS

In various aspects, the present disclosure pertains to methods ofpreparing a disclosed lubricious surface layer that is attached to acontact lens. In some aspects, the contact lens is preformed, and thedisclosed lubricious surface layer is synthesized and attached to thecontact lens after fabrication of the contact lens itself.

In various aspects, the method of preparing the surface layer to assurea crosslinking at the surface of the lens includes: controlling theconcentrations of acrylamide monomers, e.g., DMA, and a water solubleradical initiating oxidizing agent for reaction with a tertiary amine,for example, but not limited to, ammonium persulfate (APS), to form aradical in an aqueous phase at the surface of the contact lens; loadingthe lens with a desired amount of a tertiary amine, for example, but notlimited to, N,N,N′,N′-Tetramethylethane-1,2-diamine (TEMED) from anaqueous solution; and polymerizing acrylamide monomers, e.g. DMA, for adesired period of time to achieve a desired film thickness. In thismanner the initiation occurs at the surface of the lens where the TEMEDand the APS interact. In this manner a thin film of polyacrylamide,e.g., poly(DMA), is formed at the surface of the contact where theinitiator forms and polymerization results in a thin film at the lenssurface. Operating parameters are optimized to assure that DMApolymerization occurs at the lens surface without acrylamide monomer,e.g., DMA infusion, and polymerization within the lens such that changesin lens shape and physical properties are avoided.

In a further aspect the solution comprising the acrylamide monomer andthe radical initiating oxidizing, e.g., APS, can be purged of oxygen asknown to the skilled artisan, e.g., by in vacuo treatment of thesolution or bubbling nitrogen into the solution. Similarly, in someaspects, the loading solution comprising the tertiary amine can bepurged of oxygen by similar methods.

In a further aspect, the tertiary amine can be any water-solubletertiary amine. Preferably, the tertiary amine isN,N,N′,N′tetramethylethylenediamine or 3-dimethylamino)propionitrile. Ina still further aspect, the tertiary amine isN,N,N′,N′tetramethylethylenediamine (TEMED).

In various aspects, for the foregoing method, it may be more effectivefor ACUVUE® TruEye® contact lens. For O2 Optix™ and other lenses that donot display slow diffusion of APS, DMA can be pre-polymerized to highermolecular weight to reduce DMA uptake into the lens. Alternatively, morepoorly diffusing initiator systems can be used.

In other aspects, the method of preparing the surface layer to assure acrosslinking at the surface of the lens includes: loading a contact lenswith a solution comprising a hydrophobic thermal initiator, therebyproviding a hydrophobic thermal initiator loaded contact lens;optionally rinsing the contact lens following equilibration; contactingthe hydrophobic thermal initiator loaded contact lens with an aqueoussolution comprising at least one acrylamide monomer; and heating thehydrophobic thermal initiator loaded contact lens and the aqueoussolution comprising at least one acrylamide monomer. The heating can bethermal (e.g., heating the solution by heat transfer from a heat sourcesuch as an oven, heating plate and the like), UV irradiation, or acombination thereof, thereby polymerizing acrylamide monomers for adesired period of time to achieve a desired film thickness. Similarly,as described immediately above, in this manner the initiation occurs atthe surface of the lens where hydrophobic thermal initiators and theacrylamide monomers interact. Accordingly, a thin film ofpolyacrylamide, e.g., poly(DMA), is formed at the surface of the contactwhere the polymerization results in a thin film at the lens surface.

In a further aspect, the hydrophobic thermal initiator, includes, butnot limited to, but are not limited to,2,2′-azobis(2,4-dimethylpentanenitrile),2,2′-azobis(2-methylpropanenitrile), 2,2′-azobis(2-methylbutyronitrile),2,2′-azobis(2,4-dimethylvaleronitrile),1,1′-azobis(cyclohexanecarbonitrile), peroxides such as benzoylperoxide, and the like, and combinations of the foregoing. In a stillfurther aspect, the hydrophobic thermal initiator isazobisisobutyronitrile (AIBN).

In various aspects, the hydrophobic thermal initiator can be loaded intoa lens from a non-aqueous solution, for example, a C1-C6 alcoholincluding, but not limited to, an ethanol or methanol solution. In someaspects, it is desirable that the alcohol used as a solvent for thenon-aqueous solution can be extracted into water. In an alternateaspect, a hydrophobic UV initiator can be loaded into the lens and theirradiation of the lens initiates the polymerization to form the surfacefilm.

In some aspects, the initiators employed in the present disclosure canbe a commercially available free-radical initiator. The initiators arepreferably water-soluble initiators and/or monomer-soluble initiators,but can also include non-aqueous solvent-soluble initiators. Morespecifically, suitable free radical initiators include any thermal,redox or photo initiators, including, for example, alkyl peroxides,substituted alkyl peroxides, aryl peroxides, substituted aryl peroxides,acyl peroxides, alkyl hydroperoxides, substituted alkyl hydroperoxides,aryl hydroperoxides, substituted aryl hydroperoxides, heteroalkylperoxides, substituted heteroalkyl peroxides, heteroalkylhydroperoxides, substituted heteroalkyl hydroperoxides, heteroarylperoxides, substituted heteroaryl peroxides, heteroaryl hydroperoxides,substituted heteroaryl hydroperoxides, alkyl peresters, substitutedalkyl peresters, aryl peresters, substituted aryl peresters, azocompounds and halide compounds. Specific initiators include cumenehydroperoxide (CHP), t-butyl hydroperoxide (TBHP), t-butyl perbenzoate(TBPB), sodium carbonateperoxide, benzoyl peroxide (BPO), lauroylperoxide (LPO), methylethylketone peroxide 45%, potasium persulfate,ammonium persulfate, 2,2-azobis(2,4-dimethyl-valeronitrile) (VAZO®-65),1,1-azobis(cyclo-hexanecarbonitrile) (VAZO®-40),2,2-azobis(N,N′-dimethyleneisobutyramidine) dihydrochloride (VAZO®-044),2,2-azobis(2-amidinopropane) dihydrochloride (VAZO®-50) and2,2-azobis(2-amido-propane) dihydrochloride. Redox pairs such aspersulfate/sulfite and Fe(2+)/peroxide are also useful. As noted above,and as used herein, the initiator may be added to the polymerizationmixture independently or may be incorporated into another molecule, suchas a monomer (discussed below for hyper branching) or a polymer orpolymer fragment (for grafting, etc.). Initiation may also be by heat orUV light, as is known in the art, depending on the embodiment beingpracticed. Those of skill in the art can select a proper initiatorwithin the scope of this disclosure, but the most preferred initiatorfor the separation copolymers is a redox pair comprising ammoniumpersulfate and N,N,N′N′-tetramethylethylenediamine (TEMED).

In a further aspect, the free-radical initiators suitable for use in thedisclosed methods include azo and diazo compounds as discussed hereinabove, such as azo-bis-isobutyronitrile (“AIBN”), organic peroxides,hydroperoxides, persulfates and hydropersulfates, such as benzoylperoxide, inorganic peroxides and persulfates, such as theperoxide-redox systems, carbon-carbon initiators, such ashexasubstituted ethanes, and photoinitiators; numerous examples areknown in the art. See Sanchez et al., “Initiators (Free-Radical)” inKirk-Othmer Encyc. of Chem. Technol., 4th Ed., John Wiley & Sons, NewYork, 1995, Vol. 14, pp. 431-460.

Control of the polymerization reaction for preparing the polyacrylamidesin the disclosed lubricious surface layer can be provided by controllingvarious combinations of the following: selection of initiator; the ratioof monomer to initiator; and polymerization reaction conditions. Theseratios can vary depending upon the desired molecular weight, initiatorefficiency and conversion.

While specific elements and steps are discussed in connection to oneanother, it is understood that any element and/or steps provided hereinis contemplated as being combinable with any other elements and/or stepsregardless of explicit provision of the same while still being withinthe scope provided herein.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.

Since many possible aspects may be made without departing from the scopethereof, it is to be understood that all matter herein set forth orshown in the accompanying drawings and detailed description is to beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that the terminology used herein is for thepurpose of describing particular aspects only, and is not intended to belimiting. The skilled artisan will recognize many variants andadaptations of the aspects described herein. These variants andadaptations are intended to be included in the teachings of thisdisclosure and to be encompassed by the claims herein.

Now having described the aspects of the present disclosure, in general,the following Examples describe some additional aspects of the presentdisclosure. While aspects of the present disclosure are described inconnection with the following examples and the corresponding text andfigures, there is no intent to limit aspects of the present disclosureto this description. On the contrary, the intent is to cover allalternatives, modifications, and equivalents included within the spiritand scope of the present disclosure.

D. EXAMPLES

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how thecompounds, compositions, articles, devices and/or methods claimed hereinare made and evaluated, and are intended to be purely exemplary of thepresent disclosure and are not intended to limit the scope of what theinventors regard as their disclosure. Efforts have been made to ensureaccuracy with respect to numbers (e.g., amounts, temperature, etc.), butsome errors and deviations should be accounted for. Unless indicatedotherwise, parts are parts by weight, temperature is in ° C. or is atambient temperature, and pressure is at or near atmospheric.

Example 1: Representative Lubricious Coating Prepared Using DMA, TEMEDand APS

General Materials and Methods. A 30 wt % TEMED solution was prepared bypipetting 4.2 mL of deionized water (DI water) and 1.8 mL of N, N, N′,N′-tetramethylethane-1,2-diamine (“TEMED”; Sigma-Aldrich Corporation,St. Louis, Mo.; Cat. No. T22500) into glass vial. A 40 wt % DMA solutionwas prepared by pipetting 3.6 mL of DI water and 2.4 mL of N,N-dimethylacrylamide (“DMA”; Sigma-Aldrich; Cat. No. 274135) intoanother glass vial. A 1-Day Acuvue® TruEye® (narafilcon A; VistakonDivision of Johnson & Johnson Vision Care, Inc.) contact lens wasremoved from a blister pack and placed in a vial of DI water. The lenswas washed using DI water several times and soaked into the 30 wt %TEMED solution for 30 minutes. Without wishing to be bound by aparticular theory, it is believed that the soaking of the lens in TEMEDfor 30 minutes was in excess of the time required to reach equilibrium.It is believed that under these conditions equilibration of a lens withthe TEMED solution is about 15 minutes. In various aspects, it isbelieved that sufficient partial equilibration can be achieved in about5 minutes if TEMED is only needed near the surface of the lens.

The DMA solution was degassed using compressed nitrogen for 30 minutes.After degassing the DMA solution, 3 wt % of ammonium persulfate (APS;Fisher Scientific International, Inc., Hampton, N.H.; Cat. No. BP179)was added to the DMA solution. The blister pack was filled with 1 mL ofthe foregoing DMA solution. The lens which had been soaking in the TEMEDsolution was transferred to the blister pack having the DMA solution asdescribed, and polymerization allowed to proceed for 15 seconds. After15 seconds, the lens was removed and immediately dropped into a beakerof 400 mL DI water to quench the reaction. In an alternative approach,the reaction termination was achieved by submerging the lens in ablister pack containing 10 mL of DI water that was previously spargedwith O₂. Without wishing to be bound by a particular theory, it isbelieved that a high concentration of oxygen, a free radical inhibitor,terminates the reaction rapidly. Following reaction termination, themodified lens was washed by DI water several times. The modifiedlubricious lens was placed into a vial with 5 mL phosphate bufferedsaline (“PBS”) 1× without calcium and magnesium (Mediatech Inc.,Manassas, Virginia; Cat. No. 21-040-CN).

Reaction parameters. The foregoing method has at least the followingfour parameters that can be modulated: concentrations of DMA and APS inthe external phase, concentration of TEMED in the loading solution andthe reaction time. In some aspects, the disclosed methods are optimizedto provide a thin film near the surface of a contact lens. In theforegoing described method, the concentration of the initiator is highnear the surface of a contact lens, and accordingly, without wishing tobe bound by a particular theory, it is believed that polymerizationoccurs only in a thin film at and/or near the surface of the contactlens. Moreover, it is believed that it is important to ensure that DMApenetration and the resulting reaction inside the lens is minimized toprevent changes in lens shape and physical properties. Thus, measurementof diffusion coefficients of all the components in the lens wasdetermined be an important variable in choosing the best operatingparameters. Herein below measurements of transport of these componentsin lenses of interest are provided. Also, herein below, the surfacelayer is characterized for a range of operating parameters and concludeby determining parameters for a specific commercially available lens,ACUVUE® TruEye® (Vistakon Division of Johnson & Johnson Vision Care,Inc.). Although aspects of the disclosure are described herein using acommercially available ACUVUE® TruEye® lenses, it can be appreciatedthat the disclosed methods and compositions can be carried out withother hydrogel contact lens, silicon hydrogel lens, and/or other devicesthat requires the lubricity imparted by the disclosed compositions andmethods.

Diffusion Coefficients and Diffusivity. Diffusion coefficients of allthe components in the lens were determined to establish desiredoperating parameters for formation of the poly(DMA) surface layer on thelens, according to an aspect of the disclosure. The surface layer on thelens, according to an aspect of the disclosure, was characterized forpoly(DMA) layers formed over a range of operating parameters. Diffusionand partition coefficients of TEMED, DMA, and APS were determined forunmodified ACUVUE® TruEye® and 02 Optix™. Each component was loadedindividually into a lens by soaking the lens in a PBS-solutioncontaining the component for 24 hours. Subsequently, the lenses wereremoved from the solution and placed in fresh component freePBS-solution. The PBS solution was analyzed by UV-vis spectrophotometryto determine the dynamic concentration of the component released fromthe component infused lens into the PBS. The spectral results werefitted using a perfect-sink solution to Fick's 2^(nd) Law of Diffusion,Eq. 2, to determine a diffusion coefficient, D for that component. Thepartition coefficient, K, is calculated by using the volume ratio oflens and release medium, V_(lens) and V_(release), the concentration ofthe loading solution and of the final measurement of the release medium,C_(loading) and C_(release,final) as seen in Eq. 1. The resulting D andK values are tabulated in Table 1, below.

$\begin{matrix}{K = \frac{V_{release}C_{{release},{final}}}{V_{lens}C_{loading}}} & (1)\end{matrix}$ $\begin{matrix}{C_{w} = {\sum\limits_{n = 0}^{\infty}{\frac{16A_{s}{hC}_{i}}{{V_{w}\left( {{2n} + 1} \right)}^{2}\pi^{2}}e^{{- \frac{{({{2n} + 1})}^{2}\pi^{2}}{4h^{2}}}{Dt}}}}} & (2)\end{matrix}$

TABLE 1 Diffusive properties of components for lubricious layer.Diffusion Partition Coefficient, D Lens Component Coefficient, K(mm²/hr) TruEye TEMED 0.776 0.0071 DMA 0.982 0.0118 APS 0.690 0.0006 O2Optix TEMED 0.386 0.0285 DMA 0.561 0.0466 APS 0.442 0.0722

As shown in FIG. 1A and FIG. 1B, DMA and TEMED were found to have rapidreleases of around 15 minutes from ACUVUE® TruEye®, while APS was foundto have a slower release, on the order of 8 hours. Hence, the APS isplaced on the outside of the lens, as its penetration into the lens willbe low relative to the rate of polymerization. The release of APS fromO2 Optix™ was similar to that of DMA and TEMED, as indicated in FIG. 2 ,which can permit greater penetration of APS into the lens duringpolymerization.

Determination of the Surface Layer Thickness and Water Content. Thethickness of the layer is determined by measuring the difference inhydrated weight of the lenses after and before polymerization using theassumption that the DMA layer has a density of 1.00. Separately, theincrease in dry weight determined is attributed to the mass of DMApolymerized on the surface. The ratio of these weights is attributed tothe water within the coating. The weight of the lens was determinedafter soaking in DI water and after a 24 hour drying period to determinethe hydrated and dried weights respectively. After lens modification asdescribed above but before PBS storage, the lens is weighed to determineits new hydrated weight. The lens is dried for 24 hours and weighed todetermine the new dried weight. The weight differences can then bycalculated to determine both the change in water content and thethickness of the layer DMA. The thickness is calculated assuming thatadded dry weight is due solely to DMA in the lubricious layer. Assuminga uniform density and uniform thickness across the surface of the lens,the layer thickness is determined. Results for TruEye® and O2 Optix areshown in Tables 2 and 3.

TABLE 2 Results obtained with ACUVUE ® TruEye ® Contact Lens. MeasuredManufacturer Hydrated Dried water water weight weight content content(mg) (mg) (%) (%) TruEye ® (control) 38.5 ± 0.4 20.8 ± 0.5 45.9 ± 0.9 46Measured Water Hydrated Dried water Content weight weight contentIncrease (mg) (mg) (%) (%) Forumula 1 39.6 ± 0.5 21.1 ± 0.4 46.7 ± 0.61.6 TEMED 30% DMA 40% APS  3% Time (s) 10   Forumula 2 (Selected) 40.9 ±1.4 21.3 ± 03 47.9 ± 1.0 4.3 TEMED 30% DMA 40% APS  3% Time (s) 15  Forumula 3 41.3 ± 0.9 21.5 ± 0.2 48.1 ± 0.8 4.7 TEMED 30% DMA 40% APS 3% Time (s) 20   Forumula 4 40.5 ± 0.1 213 ± 0.3 47.4 ± 0.6 3.3 TEMED30% DMA 20% APS  3% Time (s) 15   Forumula 5 40.2 ± 0.3 21.3 ± 0.2 47.0± 0.3 2.3 TEMED 30% DMA 10% APS  3% Time (s) 15   Forumula 6 43.0 ± 0.421.5 ± 0.1 50.0 ± 0.6 8.9 TEMED 50% DMA 40% APS  3% Time (s) 15  Forumula 7 43.4 ± 0.4 21.4 ± 0.2 50.7 ± n/a 10.3  TEMED 40% DMA 40% APS 3% Time (s) 15   Forumula 8 41.5 ± 1.6 21.2 ± 0.2 49.0 ± n/a 6.6 TEMED20% DMA 40% APS  3% Time (s) 15  

TABLE 3 Results obtained with O2 Optix ® Contact Lens. Water Content(mg) Air-Optix aqua 10.5 Water content after Change in dry Dry filmWater content % increase in coating (mg) weight (mg) thickness (um)increase (mg) Water Content Air Optix aqua (10% 15s) 11.1 0.33 1.39 0.63.3 Air Optix aqua (20% 15s) 12.8 1.18 4.93 2.3 13.2 Air Optix aqua (40%15s) 11.1 −0.02 0.00 0.6 3.3

FIG. 3 shows a linear relationship between the increase in water weightand DMA weight. The slope of the line is roughly 2.85 which can beinterpreted to mean that the coated DMA polymer layer has a watercontent of 285%. Furthermore, the data suggest that the water content isindependent of the substrate material. FIGS. 4-6 show that water contentof the coated lens, wet weight of the film, and the dry weight of thefilm increase linearly with the reaction time. These results suggestthat the volume of the DMA film on the surface grows with time, leadingto increase in both the dry and the hydrated weight. The data from thesestudies are summarized in Table 4 below.

TABLE 4 Hydration for Various Formulations of ACUVUE TruEye ® lens.Weight of Thickness Hydrated Dried DMA of DMA weight weight coated Layer(mg) (mg) (mg) (μm) Std. Std. Std. Std. Average Dev. (±) Average Dev.(±) Average Dev. (±) Average Dev. (±) 1. Changing polymerization timeControl Lens 38.5 0.4 20.8 0.5 DMA TEMED APS Time TE 1 40 30 3 10 39.60.5 21.1 0.4 0.3 0.4 1.4 1.7 TE 2 40 30 3 15 40.9 1.4 21.3 0.3 0.5 0.32.1 1.4 TE 3 40 30 3 20 41.3 0.9 21.5 0.2 0.7 0.2 2.8 1.0 2. Changingmonomer concentration Control Lens 38.5 0.4 20.8 0.5 DMA TEMED APS TimeTE 1 10 30 3 15 40.2 0.3 21.3 0.2 0.5 0.2 2.2 0.9 TE 2 20 30 3 15 40.50.1 21.3 0.3 0.5 0.3 1.9 1.0 TE 3 40 30 3 15 40.9 1.4 21.3 0.3 0.5 0.32.1 1.4 3. Changing TEMED (inside) concentration Control Lens 38.5 0.420.8 0.5 DMA TEMED APS Time TE 1 40 20 3 15 41.5 1.6 21.2 0.2 0.4 0.21.5 0.6 TE 2 40 30 3 15 40.9 1.4 21.3 0.3 0.5 0.3 2.1 1.4 TE 3 40 40 315 43.1 0.6 21.4 0.2 0.6 0.2 2.5 0.8 TE 4 40 50 3 15 42.3 1.5 21.4 0.30.7 0.1 2.9 0.4

Characterization of Layer Thickness by Drug Release. To assign athickness of the surface layer upon polymerization, the differences indiffusivity of a component within the surface layer and the bulk of thelens was determined. The DMA layer offers a much lower diffusiveresistance relative to the silicone hydrogel core. This difference ismanifested as a burst release of a compound loaded into the modifiedcontact lens, where a portion of the compound's release is nearlyinstantaneous. Timolol maleate, a highly hydrophilic compound, wasloaded into both modified and unmodified ACUVUE® TruEye® contact lenses.The fraction of timolol maleate released through burst release can beused to approximate the added thickness of poly(DMA). Results from therelease, shown in FIG. 7 , give a burst release of 7±1% of the timololmaleate. This fraction is lower than the fractional increase in the wetweight of the poly(DMA) coated lens. The hydrated weight of the ACUVUE®TruEye® increases by about 6 mg after 15 sec polymerization duration,which is about 20% of the weight of the original lens. These differencesappear to result because the partition coefficient of timolol in the DMAcoating is likely lower than that in the bulk lens because of binding tothe silicone-hydrogel polymer. The partition coefficient of timolol inthe DMA film is close to 1 due to the very high water content, while thepartition coefficient in the ACUVUE® TruEye® lens is about 4. The burstof 7±1% is consistent with a DMA film that is about 28±4% of the totalthickness, which is within the range obtained by the weightmeasurements.

Characterization of the Surface Layer Composition by ATR-FTIR. FTIRspectra of contact lenses modified using different polymerization timesand pure poly(DMA) are shown in FIG. 8 . The pure poly(DMA) used forcomparison was prepared as follows: a 40 wt % DMA solution waspolymerized using 3% APS, and polymerization was carried out for 2 hoursunder a UVB-10 transilluminator (ULTRA⋅LUM INC, Carson, CA, USA) with anintensity of 16.50 mW/cm² and peak output at 310 nm.

The data show that the lubricious surface layer has a unique functionalgroup, a C═O carbonyl bond. In particular, a C═O bending is observed at1630 cm⁻¹ in both the pure Poly(DMA) and modified contact lens, thussuggesting that the lubricious surface layer comprises poly(DMA). FromFIG. 9 , it is observed that with increasing time, the peak area at 1630cm⁻¹ increases linearly. The peak at 700 cm⁻¹ corresponds to C═Cbending. FIG. 10 also shows a linear relationship between peak area at700 cm⁻¹ and reaction time. All the results indicate that thecomposition of the surface layer is poly(DMA) and the thickness of thesurface layer increases with longer reaction time.

Contact Angle of a Modified Contact Lens. Water contact angles ofACUVUE® TruEye® lens, before and after modification by the disclosedmethods and compositions, was measured by KRUSS drop shape analyzer (DSA100) by placing a drop of water on the surface of the lens. For lenseswith a very lubricious film, the water drop could not be kept on thesurface, so the lens was cut into a small piece that was then stretchedflat on a solid support and the drop was placed on the flattened lens.When compared to the unmodified commercial contact lens, the modifiedcontact lens has a lower water contact angle as shown in FIG. 11 , whichmeans a hydrophilic surface layer was synthesized on the surface. Thecontact angle decreases monotonically with increasing polymerizationtime FIG. 12 , consistent with thickness and density of the poly(DMA)increasing with increasing polymerization time.

Sliding Velocity Lubricity Test of a Modified Contact Lens. Thelubricity of lenses was characterized by measuring the sliding velocityon the surface of a glass inclined plane that is fully submerged inwater. The angle of incline for the glass plate was 15°; and the glassplate had dimensions of 32 cm×10 cm×0.5 cm. Plates were cleaned using(in order): acetone, methanol, and DI water prior to a series of runs. Acontact lens with a mold and a small weight was placed on the lens tomaintain contact between the lens and the glass surface. The modifiedand commercial contact lenses were placed at the same starting locationand help stationary by a glass barrier. Upon removal of the barrier thetime required for the lens to reach the bottom of the inclined plane wasdetermined. The same procedure was repeated 10 times. Table 5 shows thetotal time for lenses to travel the length of the device during eachtrial. The modified contact lens travels significantly faster thancommercial lens, suggesting a lower coefficient of friction. The ratioof the transit times cannot be inferred as the ratio of the frictioncoefficients because the motion of the lens is resisted by thesurrounding water in addition to the friction with the lens. However thesignificant decrease in the transit time suggests an increase inlubricity, which is clearly supported by tactile impressions whilerubbing the lens' surface with a finger. The data in Table 5 wereobtained with ACUVUE® TruEye® lens either unmodified or modifiedaccording to the disclosed procedures using 40 wt % DMA, 30 wt % TEMEDand 3 wt % APS. The polymerization time was 15 seconds and oxygenexposure was used to terminate the reaction. The sliding velocity datain Table 5 are provided in elapsed time (seconds).

TABLE 5 Sliding Velocity Data for ACUVUE ® TruEye ® lens (unmodified andmodified). Time for Lens—Commercial unmodified Run Run Run Run Run RunRun Run Run Run lens 1 2 3 4 5 6 7 8 9 10 Mean 2.69 2.06 2.32 1.97 2.342.34 2.67 2.50 2.41 2.22 2.35 Time for Lens—Modified modified Run RunRun Run Run Run Run Run Run Run lens 1 2 3 4 5 6 7 8 9 10 Mean 1.72 2.102.15 1.60 2.19 1.81 2.31 1.75 1.82 2.18 1.96

Torque Meter Lubricity Test of a Modified Contact Lens. In this study, acadaver rabbit cornea was used to measure the dynamic frictioncoefficient of ACUVUE® TruEye® lens either unmodified or modifiedaccording to the disclosed procedures using 40 wt % DMA, 30 wt % TEMEDand 3 wt % APS. FIGS. 44A-44D show images of the lubricity testingdevice. Briefly, a domed rod with a cornea was fixed in a torque meterwhile another concaved rod with a contact lens was placed on the cornea.The rod holding the lens was connected to a motor that provided aconstant angular speed. The value that was output by the torque was usedto calculate the friction coefficient of each individual lens.

A rabbit cornea was excised from a cadaver rabbit eye provided byPel-Freez and adhered to the top of a hemispherical domed rod usingPelco® Pro CA44 instant tissue adhesive. The domed rod was clamped inthe center of a SHIMPO TNP0.5 0.5 Capacity Torque Meter and a test lensfixed on the concaved rods. The various lenses were adhered to theconcaved rods using Elco® Pro CA44 instant tissue adhesive. Thespecialized adhesive was used because of the inherent ability thatallowed the lens to stay well fixated on the domed rod even with thelens fully hydrated. The concaved rods and lens assemblies were insertedinto the chuck and placed atop the cornea which was held in place bytracks on a forked tongue. The forked tongue was connected to a motorset to an angular speed of 18 RPM and had an additional weight (0.5 kg)placed atop the chuck to provide sufficient normal force for frictionmeasurements. The entire assembly was held in place using a largebracket the had the same height at the base as the clearance of thetorque meter, ensuring that the entire apparatus was stable during theexperiments and minimizes precession of the forked tongue, chuck, andconcaved rod about the cadaver rabbit cornea. Since the friction betweenthe chuck and the forked tongue was considered equal to the gravityforce of the chuck with the concaved rod, the gravity force of theweight is the normal force (G), which was 5N. The torque (T) wasmeasured for different lenses. The friction coefficient (μ) wascalculated using Equation 3 below where R is the radius of the rod.

$\begin{matrix}{T = {{\int_{0}^{R}{\frac{G}{\pi R^{2}}\mu{{rdr} \cdot 2}\pi r}} = {\frac{G}{\pi R^{2}}{\mu \cdot 2}\pi\frac{R^{3}}{3}}}} & 3\end{matrix}$

FIG. 45 shows representative data and indicates that torque between atest contact lens (ACUVUE® 2) and the cornea is changing periodically.Every period, or complete revolution of the motor, takes about 3.3seconds, which matches the angular speed of the motor. Each lens trialconsisted of 3 full revolutions of the motor for a total duration of 10s which output 500 data points and each trial was conducted 3 times.Each lens was tested for 1 minute and there was no data acquisition forthe first 30 seconds in order to completely negate any influence fromstatic friction. The torque was calculated from the mean value from all3 trials and using the relation in Equation 3, the friction coefficientfor each contact lens was found. It is important to note that torquedepends on the condition of the excised cornea, the rinsing or soakingsolution of the lens and concave rod assembly, the normal force, and thecontact lens material. All of these variables were consistent for eachexperiment with the exception of the lens material which is dependent onthe proprietary recipes and synthesis methods for each of the commerciallenses. The tested lenses were rinsed with phosphate-buffered saline(PBS), and the residual or superficial PBS on the lens was removed bydabbing a Kimwipe on the lens surface.

The friction coefficient of a ACUVUE® TruEye® lens either unmodified ormodified according to the disclosed procedures using 40 wt % DMA, 30 wt% TEMED and 3 wt % APS. Each lens was run 3 times in one direction. FIG.18 shows that the friction coefficient of the modified lubricious lenswas decreased by a factor of 9, which means the lubricity of themodified contact lens was highly improved.

The friction coefficient was also examined as it varies with rotationfrequency. The frequency of the motor in the test method described abovewas varied by the varying the voltage of the power source. Data were for3 runs in one direction only, and the normal force was kept constant.Friction coefficient data at different angular frequencies are shownFIG. 46 for an unmodified ACUVUE® TruEye® lens. The data show that forthis commercially available lens that the friction coefficient isrelatively constant over the range of 2.3 to 18 rpm. In contrast, datafor a modified ACUVUE® TruEye® lens, i.e., modified using 40 wt % DMA,30 wt % TEMED and 3 wt % APS with oxygen exposure to terminate thepolymerization, are shown in FIG. 47 . The data show that frictioncoefficient decreases as the rotation frequency increases for modifiedlens having a lubricious layer per the disclosed compositions andmethods.

The data regarding friction coefficient and rotation frequency arerelevant in view of the shear rates associated with contact lens and theeye are high. Without wishing to be bound by a particular theory, it isbelieved that the decrease in friction coefficient with increasingrotation frequency for the modified contact lens is related to thenormal stress component that is generated within the disclosedlubricious layer due to non-Newtonian rheology of the disclosedlubricious film. That is, the normal stress reduces the overall normalforce on the surface, and thereby reduces the effective shear force,i.e., effective friction. In terms of use by a contact lens wearer,these data are interesting because the friction coefficient is higherduring placing the lens in the eye or removing the lens from eye, butlower during an eye blink.

Summary. The approach discussed herein above comprises creating a thinregion near the surface where it is believed that the polymerizationrates are high due to a high concentration of free radicals. The highconcentration of the radicals was achieved by loading one component of aredox pair in the lens and the other component in the aqueous solutioninto which the lens is submerged. Free radicals were produced byreaction of the two components. Free radical production was likelylimited to a very thin diffusion boundary layer near the surface, bothinside and outside the lens. DMA was used as the monomer because of theknown high water content of poly(DMA), although other acrylamidemonomers can be used. It is believed that the monomer diffuses insidethe lens as well, resulting in polymerization near the surface both inthe film and outside, which results in anchoring of the film in thelens. The data herein show that the thickness of the layer growslinearly with time, which is somewhat surprising because the diffusioncontrol boundary layer thickness increases as square-root of time. Thesedata suggest that the mixing in the outer fluid could play an importantrole, and could possibly serve as another variable that may be useful toachieve the desired film thickness. Although the disclosed method doesnot include the addition of any crosslinker in the reaction step, it ispossible that the surface film could potentially be at least partiallycrosslinked through chain transfer reactions. The anchoring of thedisclosed lubricious film to a lens could either be due to covalentattachment with a few vinyl groups in the lens that were available forreaction, or due to entanglement of the polymeric DMA film inside thelens with the original lens matrix. The reaction time should be keptshort to minimize growth of the diffusion boundary layer. It is likelythat excessive reaction times could result in thick films and reactioninside the lens, which could cause shape change of the lens. In fact,the data herein suggest that the optimal reaction time for the 1-DAYACUVUE® TruEye® is 15 seconds.

The reaction time could potentially be increased if the diffusion of allthe components into the lens is slowed. To achieve this, the process wasmodified by first partially polymerizing the DMA monomer to obtainpoly(DMA), which is then used in the reaction step. Pre-polymerizing DMAdecreases the diffusivity of the poly(DMA) in the lens compared to theDMA monomer, and additionally the increased viscosity of the solutionreduces the diffusivity for the redox pair molecules as well. Thepoly(DMA) was prepared by adding 5.76 mL DI water, 4% (0.24 mL) DMA and0.3% (18 mg) thermal initiator APS into a glass vial and thenpolymerizing at 60° C. for 30 minutes. Then, 2-8 wt % monomeric DMA and1 wt % APS were added into the 4 wt % PDMA which was made in theprevious step. This was done because the poly(DMA) may not diffuse intothe lens, so the polymerized film would not form entanglements with thelens matrix. The 1-Day Acuvue® TruEye® lens was soaked into a solutionof 40 wt % TEMED and 2-8 wt % DMA for 5 minutes. The loading time ofTEMED was reduced because TEMED was only needed near the surface. Theconcentration was increased from 30 wt % to 40 wt % to ensure that therewas sufficient TEMED to drive the rapid reaction. Monomeric DMA wasloaded into the lens to help anchor the lubricious film onto the lens.After 5 minutes, the lens was removed from TEMED and placed into the 4wt % PDMA solution with 2-8 wt % DMA and 1 wt % APS for a range ofreaction times from 45-130 seconds. Finally, oxygen sparged DI water wasadded to terminate the reaction. The lens was placed into a vial of PBSfor storage.

The results of studies with varying concentration of DMA inside thelens, concentration in the outside fluid, and varying reaction time aresummarized below in Table 6. The first four columns summarize theprocess parameters and the last three summarize the quality of thesurface film. We first determined whether the shape of the lenses werechanged by visual observations. Additionally, the surface layer wasrubbed to determine whether the layer peeled. Finally, the lubricity ofthe layer on the surface after the rubbing was qualitatively evaluatedby a finger rub test. As shown in Table 6, many of the combinations ofparameters resulted in a lubricious surface film that did not rub-offand did not have a lens shape change. The studies also showed that whenthe concentration of outside monomeric DMA (the DMA which is mixed withpoly(DMA)) was increased to 8%, the shape of the lens started to change.Furthermore, when the DMA concentration both inside and outside wasincreased, the reaction time also increased. This was a beneficialresult because the approach was designed to increase the effectivereaction time. Finally, when there was no DMA present in either theinside or the outside, the surface layer was easily peeled off. Withoutwishing to be bound by a particular theory, it is hypothesized that thelink between the surface layer and lens is formed by chemical bonds andentanglement. The presence of DMA both inside and outside of the lenshelps facilitate this linkage. Based on these studies, an effectiveapproach for polymerizing a lubricious film on 1-DAY ACUVUE® TruEye®lens uses about 4 wt % poly(DMA)+4 wt % monomeric DMA in the reactionmixture and 4 wt % monomeric DMA to load the lens, with a polymerizationduration of 100 s.

TABLE 6 Modified approach based on poly(DMA). Monomer Monomer poly(DMA)DMA (Lens DMA Optimal Effort (Reaction loading (Reaction Reaction Shaperequired Lubricity after Mixture) solution) Mixture) Time/s change forpeeling rubbing/peeling 4% 4% 4% 100 N Hard Y 4% 0% 4%  45 N Easy N 4%4% 0%  90 N Easy N 4% 0% 0%  45 N Easy N 4% 2% 4% 100 N Medium Y Hard 4%4% 2%  75 N Medium Y Hard 4% 2% 2%  70 N Medium N Easy 4% 8% 4% 100 YVery Y Hard 4% 4% 8% 110 N Hard Y 4% 8% 8% 130 Y Extremely Y Hard

The results herein show that a lubricious layer in a commercial lens canbe obtained by polymerizing DMA into poly(DMA) using a redox pairinitiator. Altering the concentration of the redox initiation pair,TEMED or APS, changed the rate of polymerization. Increasing theseconcentrations caused very rapid reactions. Lower concentrations led toslower reaction times. For the selected formulation, 10 seconds ofreaction time resulted in a lubricious layer that detached afterrinsing, and 20 seconds resulted in a layer with a large thickness thataltered the lens shape. These parameters are based, in part, on thepartition coefficients and diffusivities of the components. Thefollowing parameters were considered effective for the 1-Day ACUVUE®TruEye®: 40 wt % DMA and 3 wt % APS for external solution, 30 wt % TEMEDfor loading solution, and 15 second reaction time. Other configurationscan be utilized, but may provide less desirable results. When DMA wasadded to the loading solution, lens shape changed after polymerization,which shows that polymerization occurred internally in the lens. Theresults from FTIR also proved that the composition of the lubriciouslayer was poly(DMA), and the thickness of the layer increased withincreasing reaction time. The lubricious layer created by this methodwas estimated to be 2.1±1.4 μm thick by characterization by weight and3.5±0.5 μm thick by characterization from drug release. The results fromwater contact angle test and sliding test, showed the modified lens hasa higher hydrophilicity and lubricity than the commercial lens,respectively.

As an alternative to increase reaction time, which may be desirable forcontrol during production, is based on pre-formed poly(DMA) and DMAreacting. Effective parameters for polymerizing the lubricious film on1-DAY ACUVUE® TruEye® lens by this modified approach used 4 wt %poly(DMA)+4 wt % monomeric DMA in the reaction mixture and 4 wt %monomeric DMA in the loading solution, with a polymerization reactiontime of about 100 seconds. Both approaches described above can beadapted to modify other commercial lenses, and potentially othermaterials.

Example 2: Representative Lubricious Coating Prepared Using DMA, AIBNand Heat

General Materials and Methods. 3.4% wt. AIBN solution was prepared in aglass vial using 5.0 mL methanol (Sigma-Aldrich Corporation, St. Louis,Missouri; Cat. No. 34860) and 0.17 g azobisisobutyronitrile (AIBN). 4%wt. DMA solution was prepared by pipetting 4.8 mL of deionized water (DIwater) and 0.2 mL N,N-dimethylacrylamide (“DMA”; Tokyo Chemical IndustryCo., Ltd., Singapore; Cat. No. D1091) into another glass vial. A contactlens was washed by DI water several times and soaked into the 3.4 wt %AIBN solution for 30 minutes. Then, the lens was transferred to PBS andrinsed for 5 minutes. The contact lens was placed into the 4 wt % DMAsolution which has been purged with N₂ for 40 minutes. The 4 wt % DMAsolution with the contact lens was kept at 70° C. for 12 hours. If thetemperature is kept at 85° C., the reaction time can be reduced to 1.5hours. Then, the modified lubricious lens was washed by DI water severaltimes and placed into a glass vial with 5 mL phosphate buffered saline1× (“PBS”) without calcium and magnesium (Mediatech Inc., Manassas,Virginia; Cat. No. 21-040-CN). The foregoing method is schematicallyillustrated in FIG. 14 .

Reaction parameters. It is important to note that the initiator used inthe foregoing method to initiate the reaction, AIBN, is hydrophobic. Assuch, it does not diffuse into the aqueous phase, and accordinglylimiting the possibility of polymerization in the external phase.However, since AIBN can be broken into free radicals and nitrogen gas athigh temperature (Bartlett P. D., et al., J. Amer. Chem. So. (1960)82(7):1762-1768), and the free radicals have a high solubility in water.Accordingly, it is believed, in the foregoing method, that theconcentration of the free radicals near the lens surface is high.Moreover, the termination rate of the free radical is high (k=6.32*10⁶min⁻¹; see Achilias D. and Kiparissides C. Poly. Sci. (2010)35(5):1303-1323). Thus, it is believed that polymerization occurs onlyin the coating film. Different concentrations of DMA may alter thediffusion rate into a lens, which can lead to a shape change and loss oflubricity. The foregoing method has at least the following parametersthat can be modulated: concentration of DMA in the aqueous phase, i.e.,external phase to the lens; concentration of AIBN loaded in the lens;and the reaction time. In the experiments described herein below, thelubricious surface layer was characterized as related to these threeparameters. Moreover, the parameters were examined as they relate to thelubricious surface characteristics with regard to a commerciallyavailable lens, ACUVUE® ADVANCE® ((Vistakon Division of Johnson &Johnson Vision Care, Inc.). Although aspects of the disclosure aredescribed herein using a commercially available ACUVUE® ADVANCE® lens,it can be appreciated that the disclosed methods and compositions can becarried out with other hydrogel contact lens, silicon hydrogel lens,and/or other devices that requires the lubricity imparted by thedisclosed compositions and methods, e.g., AIR OPTIX® contact lens (AlconLaboratories, Inc., Fort Worth, Texas).

Determination of the Water Content in Modified Lens. The water contentof the modified lens was assessed by measuring the difference betweenhydrated weight and dry weight of the lubricious lenses. Table 7 belowshows the dry weight and hydrated weight for both a commercial lens anda modified lens. The weight of the hydrated layer and the dry layer wascalculated by subtracting the weight of the commercial lens from theweight of the modified one. The ratio of the weights (in grams) of thehydrated layer and the dry layer yields the water content in thelubricious layer (see Table 7). The data Table 7 were obtained using anACUVUE® ADVANCE® lens that was unmodified or modified according to thepreceding method using 3.4 wt % AIBN and 4 wt % DMA, and reaction at 70°C. for 12 hours.

TABLE 7 Characterization of modified contact lens weight. Lens Lens LensHydrated Layer Lens Dried Layer Water Water Hydrated mass Hydrated Driedmass Dried content content Type mass (average) mass mass (average) mass(lens) (layer) Unmodified 0.0333 0.0333 — 0.0168 0.0168 — 49.550% — LensModified 0.0475 0.0474 0.0141 0.0202 0.0195 0.00273 58.790% 415.854%Lens 0.0467 0.0190 0.0480 0.0194

Lens were modified by the foregoing method to assess the effect ofvarying each of: concentration of DMA, concentration of AIBN, andreaction times. FIGS. 19-21 show that the water content of modifiedlenses, the wet weight of the film, and the dry weight of the filmincreased as the concentration of DMA increased at concentrationsgreater than 3%. FIGS. 22-24 show that the water content of modifiedlenses, the wet weight of the film, and the dry weight of the filmincreased as the concentration of AIBN increased at concentrationsgreater than 3%. FIGS. 25-27 show that the water content of modifiedlenses, the wet weight of the film, and the dry weight of the filmincreased within the first three hours reaction and then appeared toreach a plateau. The data pertaining to reaction time suggest that the asignificant proportion of polymerization likely occurred, under theseconditions, within the first three hours of reaction.

Contact Angle of Modified Lens. The water contact angle of an ACUVUE®ADVANCE® unmodified lens and an ACUVUE® ADVANCE® lens modified per theforegoing methods was determined using a KRÜSS Drop ShapeAnalyzer—DSA100. Briefly, a drop of water was placed on the surface of atest lens. The data show that a modified contact lens compared to theunmodified contact lens, the modified contact lens has a significantlylower water contact angle (FIG. 15 ), suggesting that a hydrophilicsurface layer was on the surface as a result of the foregoing method.Specifically, the contact angle (theta) of water on the surface of anunmodified ACUVUE® ADVANCE® lens was 105.9±0.1 degree, whereas thecontact angle (theta) of a modified ACUVUE® ADVANCE® lens was 45.3±0.12degree. The data in show that the contact angle decreased monotonicallyas concentration of DMA increased at concentrations greater than 3 wt %(FIG. 28 ); as concentration of AIBN increased at concentrations greaterthan 3 wt % (FIG. 29 ), and with increasing reaction time (FIG. 30 ).The results suggest that thickness of the disclosed lubricous layer canbe increased with higher concentration of DMA, AIBN or longer reactionduration.

Lubricity and Shape Change of a Modified Lens. Assessment of the variousparameters, the concentration of AIBN and DMA were varied. All studieswere carried at the indicated concentrations of AIBN and DMA accordingto the foregoing method with reactions carried out at 70° C. and 12hours. FIG. 31 shows the images of lens modified as described; adescription of shape assessed visually; and lubricity characteristicsassessed by a finger feel test involving rubbing the surface with thefingers. The data show that higher concentrations of DMA and AIBN can beassociated with a lens shape change; and a lower concentration of DMAand AIBN can be associated with a loss of lubricity. In some aspects, aneffective concentration of AIBN and DMA are 3.4 wt % and 4 wt %.

Characterization of the Surface Layer Composition by ATR-FTIR. ACUVUE®ADVANCE® lens modified per the foregoing methods was analyzed usingFTIR, and the FTIR spectra obtained were compared to FTIR spectraobtained for an ACUVUE® ADVANCE® unmodified lens and a solution sampleof poly(dimethyl acrylamide). The FTIR spectra are shown in FIGS. 32-34obtained for varied concentrations of DMA or AIBN, and also for variedreaction times. The data show that as the concentration of DMA and AIBNincreased at concentrations greater than 3%, the FTIR spectra of themodified contact lens becomes increasingly similar to the spectra ofpoly(dimethyl acrylamide). Similar results were obtained for variedreaction time, i.e., that as reaction time increased the FTIR spectra ofthe modified lens showed increased similarity to the FTIR spectra of apoly(dimethyl acrylamide) sample. The data are consistent with thesurface layer being substantially similar to poly(dimethyl acrylamide).In addition, the data are consistent with the thickness of the surfacelayer increasing with the same parameters.

Lubricity Test of a Modified Contact Lens. The lubricity of the lenseswere characterized by measuring the friction coefficient between lensesand a rabbit cornea as described herein above using the Torque MeterLubricity Test. Both ACUVUE® ADVANCE® unmodified lens and an ACUVUE®ADVANCE® lens modified per the foregoing methods were tested. Thefriction coefficient of each lens was measured for 3 runs in onedirection only. FIG. 35 shows the friction coefficient of the modifiedlubricious lens decreased by the factor of 5, consistent with thelubricity of the modified contact lens being highly improved compared tothe unmodified lens.

Assessment of the Disclosed Method with Other Lens. The foregoing methodwas applied to other commercially available lens, such as, ACUVUE®Oasys, ACUVUE® 2, ACUVUE® Trueye®, DAILIES TOTAL1®, DAILIES® AquaComfortPlus®, Air Optix®, Avaira®. However, only ACUVUE® ADVANCE® and AirOptix® lens were effectively modified under these conditions.Modification according to these procedures on other lenses caused ashape change or failed to add lubricity on the surface. Each brand usesdifferent materials in their lenses, which leads to unique AIBN releaseprofiles from the lenses into the DMA solution (external solution). Thelenses were soaked in 3.4% AIBN (methanol) solution for 24 hours, andthen transferred into DI water at 80° C. The DI water was analyzed usingUV-vis spectrophotometry to determine the dynamic concentration of AIBNthat was released into the DI water. FIG. 36 shows AIBN release at 80°C. for these selected lenses. We observed that ACUVUE® ADVANCE® and AirOptix® lenses released effective amounts of AIBN in 30 minutes capableof catalyzing synthesis of the lubricious layer. The data suggest thatother lenses did not release an effective amount of AIBN within thistime scale. ACUVUE® Oasys, ACUVUE® 2, ACUVUE® Trueye®, DAILIES TOTAL1®,and DAILIES® AquaComfort Plus® lenses released a substantial proportionof AIBN within 5 minutes, with a kinetic profile similar to that seenfor ACUVUE® ADVANCE® and Air Optix®. In contrast, the Avaira® lensreleased only a small amount of AIBN over an extended period of about 3hours. However, there was no observed no lubricity on the lens surfaceor a lens shape change.

As an alternative approach, in order to modulate the release of AIBNfrom the lens, the ability of vitamin E to act as an effective diffusionbarrier was examined for ACUVUE® Oasys, ACUVUE®2, and ACUVUE® Trueye®lens. Briefly, the lens was soaked in a methanol solution of the VitaminE and AIBN (1.8 wt % Vitamin E and 7 wt % AIBN) for 24 hours. Followingsoaking of the lens in the foregoing solution, it was placed in DI waterat 80° C. The DI water was analyzed using UV-vis spectrophotometrydetermine the release of AIBN versus time. FIG. 37 shows AIBN releasefrom these lenses loaded with both Vitamin E and AIBN. The data suggeststhat the presence of Vitamin E slows the release of AIBN from theselenses, and is especially notable for the ACUVUE® Oasys.

Synthesis of a lubricious layer was attempted, using the modified methodwith vitamin E, for an ACUVUE® Oasys lens. Briefly, an Acuvue Oasys lenswas soaked in a methanol solution of Vitamin E and AIBN (1.8 wt %Vitamin E and 7 wt % AIBN) for 1 hour. The lens was transferred into avial of 4% DMA solution which had been purged with nitrogen for 30minutes. The vial was kept at 80° C. for 12 hours, washed with DI water,and then placed into a vial of PBS. The lubricity of an unmodified andmodified ACUVUE® Oasys lens by the lubricity testing device describedabove. The data in FIG. 38 show that the friction coefficient of themodified lens was 6 times lower than the commercial lens, indicatingthat the lubricity of the modified Acuvue Oasys was highly improved.

Summary. The data herein demonstrate a method utilizing DMA and AIBNusing heat can provide a surface layer modification to commerciallyavailable contact lens that increases lubricity and wettability. Thatis, the data show a contact lens can be modified to comprise alubricious surface layer comprising poly(dimethyl acrylamide) can beprepared using DMA and a hydrophobic initiator, AIBN. The method can becontrolled more easily than the method in Example 1 due to the extendedreaction times, such that the reaction time is on the order of severalhours, e.g., about 12 hours can be effective. The concentration ofmonomer, e.g., DMA, and initiator, e.g., AIBN, can be controlled toinsure effective results. For example, it was observed that highconcentrations of DMA or AIBN can lead to detrimental results, includinga shape change or lack of lubricity. It was also observed that thereaction time should be can be optimized for effective results, e.g., atoo short reaction time can also result in a low lubricity on the lenssurface. The following parameters were considered highly effective for1-Day ACUVUE® Advance® lens: about 4 wt % DMA for the external solution;about 3.4 wt % AIBN for the lens loading solution; and about 12 hoursreaction time at about 70° C. Other configurations were examined, buthad less effective surface layers. The results from FTIR are consistentwith the composition of the lubricious surface layer comprisingpoly(dimethyl acrylamide). It was observed that the thickness of thesurface layer increased with increasing concentration of DMA, increasingconcentration of AIBN, and increasing reaction time. The results fromwater contact angle tests and lubricity tests showed the modified lenshas a higher hydrophilicity and lubricity than the commercial lenses.AIBN release from lenses at high temperature was analyzed. Vitamin E wasintroduced as a diffusion barrier to decrease the rate of the AIBNrelease. An ACUVUE® OASYS® lens loaded with Vitamin E and AIBN waseffectively modified to comprise an effective lubricious surface layerthat was significantly improved compared to the same lens withoutmodification.

Example 3: Representative Lubricious Coating Prepared Using DMA, AIBNand UV Irradiation

Synthesis of Lubricious Layer Using UV Irradiation. The application ofthe foregoing method using DMA and AIBN to other lens types was examinedby modified the modality of carrying out the reaction. In the abovemethod, the reaction of DMA and AIBN was facilitated by heating. In amodified approach, shown schematically in FIG. 16 , the reaction wascarried out using UV irradiation as an energy source for the reaction.Briefly, a contact lens was soaked in a methanol solution of 3.0 wt %azobisisobutyronitrile (AIBN) for 30 minutes. Then, after transferringthe lens to PBS and rinsing for 2 minutes, the contact lens was placedinto an aqueous solution (DI water) of 40 wt % N, N-dimethylacrylamidewhich had been purged for 40 minutes. The 40 wt % DMA solution with thecontact lens was placed under UV light for 20 seconds. The UV lightsource was an RC-742 Pulsed UV System (Xenon Corporation, Wilmington,Mass.). The RC-742 Pulsed UV System is capable of producing 1,000 W/cm²in under 0.5 second, and the lamps operate without a magnetron and canbe ozone-free. Following polymerization, the lens was then washed withDI water and stored in PBS.

The data are summarized in FIGS. 40 and 41 , and these data suggest thatthe use of UV irradiation is highly effective for synthesizing alubricious layer on the ACUVUE® Oasys lens. However, the effectivenesswas more limited for other lenses examined. Based on the foregoingresults, the characteristics of the lubricious layer synthesized in thepresence of UV irradiation was examined in further detail for theACUVUE® Oasys lens. Alternative concentrations of AIBN were alsoexamined using UV irradiation as the energy source. The data for theseadditional reaction variations are shown in FIG. 42 . The shape oflubricious contact lens was not changed by the modification at higherAIBN concentrations, but the size of lens was observed to be enlarged,with the perimeter of the modified lens was increased by 118% comparedto the unmodified lens, see FIG. 39 . The modified lens shown in FIG. 39was prepared using 40 wt % DMA and 3 wt % AIBN, and reaction under UVlight as described above.

Determination of the Water Content in Modified Lens. The water contentof the modified lens was assessed by measuring the difference betweenhydrated weight and dry weight of the lubricious lenses. Table 8 belowshows the dry weight and hydrated weight for both a commercial lens anda modified lens. The weight of the hydrated layer and the dry layer wascalculated by subtracting the weight of the commercial lens from theweight of the modified one. The ratio of the weights (in grams) of thehydrated layer and the dry layer yields the water content in thelubricious layer (see Table 8). The data Table 8 were obtained using anACUVUE® ADVANCE® lens that was unmodified or modified according to thepreceding method using 3.0 wt % AIBN and 40 wt % DMA, and reactioncarried out under UV irradiation.

TABLE 8 Characterization of modified contact lens weight. Lens Lens LensHydrated Layer Lens Dried Layer Water Water Hydrated mass Hydrated Driedmass Dried content content Type mass (average) mass mass (average) mass(lens) (layer) Unmodified 0.0306 0.0306 — 0.0188 0.0188 — 38.562% — LensModified 0.0434 0.0437 0.0131 0.0213 0.0208 0.00197 52.443% 564.407%Lens 0.0438 0.0209 0.0438 0.0201

Contact Angle of Modified Lens. The water contact angle was determinedusing a KRÜSS Drop Shape Analyzer—DSA100 for an ACUVUE® Oasys unmodifiedlens and an ACUVUE® Oasys lens modified per the foregoing method usingUV irradiation. Briefly, a drop of water was placed on the surface of atest lens. The data show that a modified contact lens compared to theunmodified contact lens, the modified contact lens has a significantlylower water contact angle (FIG. 17 ), suggesting that a hydrophilicsurface layer was on the surface as a result of the foregoing method.Specifically, the contact angle (theta) of water on the surface of anunmodified ACUVUE® Oasys lens was 95.5±0.84 degree, whereas the contactangle (theta) of a modified ACUVUE® Oasys lens was 52.3±1.32 degree. Theresults suggest that thickness of the disclosed lubricous layer can beincreased with higher concentration of DMA, AIBN or longer reactionduration.

Lubricity Test of a Modified Contact Lens. The lubricity of the lenseswere characterized by measuring the friction coefficient between lensesand a rabbit cornea as described herein above using the Torque MeterLubricity Test. Both an ACUVUE® Oasys unmodified lens and an ACUVUE®Oasys lens modified per the foregoing methods using UV irradiation weretested. The friction coefficient of each lens was measured for 3 runs inone direction only with the test lens and rabbit cadaver cornea hydratedin PBS. In the test, the load was 4.9N and the angular speed was 15 RPM.The data in FIG. 43 show that the friction coefficient of the modifiedlubricious lens decreased by the factor of 4, consistent with thelubricity of the modified contact lens being highly improved compared tothe unmodified lens.

Summary. The data herein demonstrate a method utilizing DMA and AIBNusing UV irradiation can provide a surface layer modification tocommercially available contact lens that increases lubricity andwettability. That is, the data show a contact lens can be modified tocomprise a lubricious surface layer comprising poly(dimethyl acrylamide)can be prepared using DMA and a hydrophobic initiator, AIBN. The methodcan be controlled more easily than the method in Example 1 due to theability to exquisitely control aspects of the UV irradiation such asintensity, duration, and wavelength of the UV irradiation. In variousaspects, it was determined that this modified method could provide aneffective lubricious surface layer to an ACUVUE® OASYS® lens. Effectiveparameters for this method using an ACUVUE® OASYS® lens were: about 40wt % DMA in the external solution; about 3 wt % AIBN in the lens loadingsolution; and UV irradiation for about 20 seconds.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present disclosurewithout departing from the scope or spirit of the present disclosure.Other aspects of the present disclosure will be apparent to thoseskilled in the art from consideration of the specification and practiceof the present disclosure disclosed herein. It is intended that thespecification and examples be considered as exemplary only, with a truescope and spirit of the present disclosure being indicated by thefollowing claims.

What is claimed is:
 1. A hydrogel contact lens, consisting of a hydrogelcontact lens body and a surface layer of relatively uniform thickness,wherein the surface layer consists of a non-ionic hydrophilic polymerattached to a hydrogel surface of the hydrogel contact lens by a linkbetween the surface layer and the hydrogel contact lens body, andwherein the non-ionic hydrophilic polymer is a polyacrylamide.
 2. Thehydrogel contact lens of claim 1, wherein the lens is a siliconehydrogel contact lens.
 3. The hydrogel contact lens of claim 2, whereinthe silicone hydrogel contact lens body is a narafilcon A contact lens,a lotrafilcon B contact lens, a galyfilcon A contact lens, or asenofilcon A contact lens.
 4. The hydrogel contact lens of claim 1,wherein the surface layer is a film.
 5. The hydrogel contact lens ofclaim 1, wherein the surface layer does not substantially alter theshape of the hydrogel contact lens body.
 6. The hydrogel contact lens ofclaim 1, wherein the link is a reaction product of a precursor of thenon-ionic hydrophilic polymer and tertiary amine, a radical initiator,or both a tertiary amine and a radical initiator.
 7. The hydrogelcontact lens of claim 6, wherein the tertiary amine isN,N,N′,N′-tetramethylethylenediamine (TEM ED) or3-(dimethylamino)propionitrile.
 8. The hydrogel contact lens of claim 6,wherein the radical initiator is a thermal initiator, a redox initiator,a photo initiator, or any combination thereof.
 9. The hydrogel contactlens of claim 6, wherein the radical initiator is selected from thegroup consisting of ammonium persulfate (APS), azobisisobutyronitrile(AIBN), cumene hydroperoxide (CHP), t-butyl hydroperoxide (TBHP),t-butyl perbenzoate (TBPB), sodium carbonateperoxide, benzoyl peroxide(BPO), lauroyl peroxide (LPO), methylethylketone peroxide 45%, potassiumpersulfate, 2,2-azobis(2,4-dimethyl-valeronitrile),1,1-azobis(cyclo-hexanecarbonitrile),2,2-azobis(N,N′-dimethyleneisobutyramidine) dihydrochloride,2,2-azobis(2-amidinopropane) dihydrochloride,2,2-azobis(2-amido-propane) dihydrochloride, and combinations thereof.10. The hydrogel contact lens of claim 6, wherein the tertiary amine isTEMED and the radical initiator is APS.
 11. The hydrogel contact lens ofclaim 1, wherein the polyacrylamide monomer units are selected from thegroup consisting of acrylamide; methacrylamide; N-ethylacrylamide,N-isopropylacrylamide, N-tert-butylacrylamide; N-ethylmethacrylamide;N-isopropylmethacrylamide; N, N-dimethylacrylamide; N,N-diethyl-acrylamide; N-[3dimethylamino)propyl]acrylamide;N-[3-(diethylamino)propyl]acrylamide;N-[3-dimethylamino)propyl]methacrylamide;N-[3-(diethylamino)propyl]methacrylamide, and combinations thereof. 12.The hydrogel contact lens of claim 11, wherein the polyacrylamide ispoly(N,N-dimethylacrylamide).
 13. The hydrogel contact lens of claim 1,wherein the hydrogel contact lens has a water contact angle of from 15degrees to 60 degrees.
 14. The hydrogel contact lens of claim 1, whereinthe surface layer has a thickness of from about 0.9 μm to about 1.7 μm.15. The hydrogel contact lens of claim 1, wherein the hydrogel contactlens has a friction coefficient at least a factor of 4 lower than anotherwise identical lens lacking the surface layer.
 16. The hydrogelcontact lens of claim 1, wherein the surface layer has a water swellingratio greater than 200%.
 17. The hydrogel contact lens of claim 1,wherein the hydrogel contact lens has a water content at increase offrom about 1.6% to about 10.3% relative to an otherwise identical lenslacking the surface layer.
 18. The hydrogel contact lens of claim 1,wherein the hydrogel contact lens has not been subjected to a plasmasurface treatment.